diff --git a/backend/azureblob/azureblob.go b/backend/azureblob/azureblob.go
index 58f4552b9..971bdc1d1 100644
--- a/backend/azureblob/azureblob.go
+++ b/backend/azureblob/azureblob.go
@@ -539,10 +539,10 @@ func NewFs(ctx context.Context, name, root string, m configmap.Mapper) (fs.Fs, e
 
 	err = checkUploadChunkSize(opt.ChunkSize)
 	if err != nil {
-		return nil, fmt.Errorf("azure: chunk size: %w", err)
+		return nil, fmt.Errorf("chunk size: %w", err)
 	}
 	if opt.ListChunkSize > maxListChunkSize {
-		return nil, fmt.Errorf("azure: blob list size can't be greater than %v - was %v", maxListChunkSize, opt.ListChunkSize)
+		return nil, fmt.Errorf("blob list size can't be greater than %v - was %v", maxListChunkSize, opt.ListChunkSize)
 	}
 	if opt.Endpoint == "" {
 		opt.Endpoint = storageDefaultBaseURL
@@ -551,12 +551,12 @@ func NewFs(ctx context.Context, name, root string, m configmap.Mapper) (fs.Fs, e
 	if opt.AccessTier == "" {
 		opt.AccessTier = string(defaultAccessTier)
 	} else if !validateAccessTier(opt.AccessTier) {
-		return nil, fmt.Errorf("Azure Blob: Supported access tiers are %s, %s and %s",
+		return nil, fmt.Errorf("supported access tiers are %s, %s and %s",
 			string(azblob.AccessTierHot), string(azblob.AccessTierCool), string(azblob.AccessTierArchive))
 	}
 
 	if !validatePublicAccess((opt.PublicAccess)) {
-		return nil, fmt.Errorf("Azure Blob: Supported public access level are %s and %s",
+		return nil, fmt.Errorf("supported public access level are %s and %s",
 			string(azblob.PublicAccessBlob), string(azblob.PublicAccessContainer))
 	}
 
@@ -598,7 +598,7 @@ func NewFs(ctx context.Context, name, root string, m configmap.Mapper) (fs.Fs, e
 	case opt.UseEmulator:
 		credential, err := azblob.NewSharedKeyCredential(emulatorAccount, emulatorAccountKey)
 		if err != nil {
-			return nil, fmt.Errorf("Failed to parse credentials: %w", err)
+			return nil, fmt.Errorf("failed to parse credentials: %w", err)
 		}
 		u, err = url.Parse(emulatorBlobEndpoint)
 		if err != nil {
@@ -644,7 +644,7 @@ func NewFs(ctx context.Context, name, root string, m configmap.Mapper) (fs.Fs, e
 		})
 
 		if err != nil {
-			return nil, fmt.Errorf("Failed to acquire MSI token: %w", err)
+			return nil, fmt.Errorf("failed to acquire MSI token: %w", err)
 		}
 
 		u, err = url.Parse(fmt.Sprintf("https://%s.%s", opt.Account, opt.Endpoint))
@@ -679,7 +679,7 @@ func NewFs(ctx context.Context, name, root string, m configmap.Mapper) (fs.Fs, e
 	case opt.Account != "" && opt.Key != "":
 		credential, err := azblob.NewSharedKeyCredential(opt.Account, opt.Key)
 		if err != nil {
-			return nil, fmt.Errorf("Failed to parse credentials: %w", err)
+			return nil, fmt.Errorf("failed to parse credentials: %w", err)
 		}
 
 		u, err = url.Parse(fmt.Sprintf("https://%s.%s", opt.Account, opt.Endpoint))
@@ -699,7 +699,7 @@ func NewFs(ctx context.Context, name, root string, m configmap.Mapper) (fs.Fs, e
 		parts := azblob.NewBlobURLParts(*u)
 		if parts.ContainerName != "" {
 			if f.rootContainer != "" && parts.ContainerName != f.rootContainer {
-				return nil, errors.New("Container name in SAS URL and container provided in command do not match")
+				return nil, errors.New("container name in SAS URL and container provided in command do not match")
 			}
 			containerURL := azblob.NewContainerURL(*u, pipeline)
 			f.cntURLcache[parts.ContainerName] = &containerURL
@@ -727,7 +727,7 @@ func NewFs(ctx context.Context, name, root string, m configmap.Mapper) (fs.Fs, e
 		pipe := f.newPipeline(azblob.NewTokenCredential("", tokenRefresher), options)
 		serviceURL = azblob.NewServiceURL(*u, pipe)
 	default:
-		return nil, errors.New("No authentication method configured")
+		return nil, errors.New("no authentication method configured")
 	}
 	f.svcURL = &serviceURL
 
@@ -1337,7 +1337,7 @@ func (o *Object) Hash(ctx context.Context, t hash.Type) (string, error) {
 	}
 	data, err := base64.StdEncoding.DecodeString(o.md5)
 	if err != nil {
-		return "", fmt.Errorf("Failed to decode Content-MD5: %q: %w", o.md5, err)
+		return "", fmt.Errorf("failed to decode Content-MD5: %q: %w", o.md5, err)
 	}
 	return hex.EncodeToString(data), nil
 }
@@ -1527,7 +1527,7 @@ func (o *Object) Open(ctx context.Context, options ...fs.OpenOption) (in io.Read
 	var offset int64
 	var count int64
 	if o.AccessTier() == azblob.AccessTierArchive {
-		return nil, fmt.Errorf("Blob in archive tier, you need to set tier to hot or cool first")
+		return nil, fmt.Errorf("blob in archive tier, you need to set tier to hot or cool first")
 	}
 	fs.FixRangeOption(options, o.size)
 	for _, option := range options {
@@ -1752,7 +1752,7 @@ func (o *Object) AccessTier() azblob.AccessTierType {
 // SetTier performs changing object tier
 func (o *Object) SetTier(tier string) error {
 	if !validateAccessTier(tier) {
-		return fmt.Errorf("Tier %s not supported by Azure Blob Storage", tier)
+		return fmt.Errorf("tier %s not supported by Azure Blob Storage", tier)
 	}
 
 	// Check if current tier already matches with desired tier
@@ -1768,7 +1768,7 @@ func (o *Object) SetTier(tier string) error {
 	})
 
 	if err != nil {
-		return fmt.Errorf("Failed to set Blob Tier: %w", err)
+		return fmt.Errorf("failed to set Blob Tier: %w", err)
 	}
 
 	// Set access tier on local object also, this typically
diff --git a/backend/azureblob/imds.go b/backend/azureblob/imds.go
index b23e91d62..84c6379e6 100644
--- a/backend/azureblob/imds.go
+++ b/backend/azureblob/imds.go
@@ -119,7 +119,7 @@ func GetMSIToken(ctx context.Context, identity *userMSI) (adal.Token, error) {
 
 	b, err := ioutil.ReadAll(resp.Body)
 	if err != nil {
-		return result, fmt.Errorf("Couldn't read IMDS response: %w", err)
+		return result, fmt.Errorf("couldn't read IMDS response: %w", err)
 	}
 	// Remove BOM, if any. azcopy does this so I'm following along.
 	b = bytes.TrimPrefix(b, []byte("\xef\xbb\xbf"))
@@ -130,7 +130,7 @@ func GetMSIToken(ctx context.Context, identity *userMSI) (adal.Token, error) {
 	// storage API call.
 	err = json.Unmarshal(b, &result)
 	if err != nil {
-		return result, fmt.Errorf("Couldn't unmarshal IMDS response: %w", err)
+		return result, fmt.Errorf("couldn't unmarshal IMDS response: %w", err)
 	}
 
 	return result, nil
diff --git a/backend/cache/cache.go b/backend/cache/cache.go
index fc038f6ad..1c75aea4a 100644
--- a/backend/cache/cache.go
+++ b/backend/cache/cache.go
@@ -1128,7 +1128,7 @@ func (f *Fs) ListR(ctx context.Context, dir string, callback fs.ListRCallback) (
 				case fs.Directory:
 					_ = f.cache.AddDir(DirectoryFromOriginal(ctx, f, o))
 				default:
-					return fmt.Errorf("Unknown object type %T", entry)
+					return fmt.Errorf("unknown object type %T", entry)
 				}
 			}
 
diff --git a/backend/cache/plex.go b/backend/cache/plex.go
index e3a333c73..09ea47233 100644
--- a/backend/cache/plex.go
+++ b/backend/cache/plex.go
@@ -213,7 +213,7 @@ func (p *plexConnector) authenticate() error {
 	var data map[string]interface{}
 	err = json.NewDecoder(resp.Body).Decode(&data)
 	if err != nil {
-		return fmt.Errorf("failed to obtain token: %v", err)
+		return fmt.Errorf("failed to obtain token: %w", err)
 	}
 	tokenGen, ok := get(data, "user", "authToken")
 	if !ok {
diff --git a/backend/cache/storage_persistent.go b/backend/cache/storage_persistent.go
index 0de9a3963..eb36a0806 100644
--- a/backend/cache/storage_persistent.go
+++ b/backend/cache/storage_persistent.go
@@ -250,7 +250,7 @@ func (b *Persistent) GetDirEntries(cachedDir *Directory) (fs.DirEntries, error)
 		if val != nil {
 			err := json.Unmarshal(val, cachedDir)
 			if err != nil {
-				return fmt.Errorf("error during unmarshalling obj: %v", err)
+				return fmt.Errorf("error during unmarshalling obj: %w", err)
 			}
 		} else {
 			return fmt.Errorf("missing cached dir: %v", cachedDir)
@@ -551,7 +551,7 @@ func (b *Persistent) CleanChunksBySize(maxSize int64) {
 	err := b.db.Update(func(tx *bolt.Tx) error {
 		dataTsBucket := tx.Bucket([]byte(DataTsBucket))
 		if dataTsBucket == nil {
-			return fmt.Errorf("Couldn't open (%v) bucket", DataTsBucket)
+			return fmt.Errorf("couldn't open (%v) bucket", DataTsBucket)
 		}
 		// iterate through ts
 		c := dataTsBucket.Cursor()
@@ -901,16 +901,16 @@ func (b *Persistent) rollbackPendingUpload(remote string) error {
 		v := bucket.Get([]byte(remote))
 		err = json.Unmarshal(v, tempObj)
 		if err != nil {
-			return fmt.Errorf("pending upload (%v) not found %v", remote, err)
+			return fmt.Errorf("pending upload (%v) not found: %w", remote, err)
 		}
 		tempObj.Started = false
 		v2, err := json.Marshal(tempObj)
 		if err != nil {
-			return fmt.Errorf("pending upload not updated %v", err)
+			return fmt.Errorf("pending upload not updated: %w", err)
 		}
 		err = bucket.Put([]byte(tempObj.DestPath), v2)
 		if err != nil {
-			return fmt.Errorf("pending upload not updated %v", err)
+			return fmt.Errorf("pending upload not updated: %w", err)
 		}
 		return nil
 	})
@@ -966,11 +966,11 @@ func (b *Persistent) updatePendingUpload(remote string, fn func(item *tempUpload
 		}
 		v2, err := json.Marshal(tempObj)
 		if err != nil {
-			return fmt.Errorf("pending upload not updated %v", err)
+			return fmt.Errorf("pending upload not updated: %w", err)
 		}
 		err = bucket.Put([]byte(tempObj.DestPath), v2)
 		if err != nil {
-			return fmt.Errorf("pending upload not updated %v", err)
+			return fmt.Errorf("pending upload not updated: %w", err)
 		}
 
 		return nil
diff --git a/backend/compress/compress.go b/backend/compress/compress.go
index 6d3397dfb..dcc54a11c 100644
--- a/backend/compress/compress.go
+++ b/backend/compress/compress.go
@@ -222,7 +222,7 @@ func processFileName(compressedFileName string) (origFileName string, extension
 	// Separate the filename and size from the extension
 	extensionPos := strings.LastIndex(compressedFileName, ".")
 	if extensionPos == -1 {
-		return "", "", 0, errors.New("File name has no extension")
+		return "", "", 0, errors.New("file name has no extension")
 	}
 	extension = compressedFileName[extensionPos:]
 	nameWithSize := compressedFileName[:extensionPos]
@@ -231,11 +231,11 @@ func processFileName(compressedFileName string) (origFileName string, extension
 	}
 	match := nameRegexp.FindStringSubmatch(nameWithSize)
 	if match == nil || len(match) != 3 {
-		return "", "", 0, errors.New("Invalid filename")
+		return "", "", 0, errors.New("invalid filename")
 	}
 	size, err := base64ToInt64(match[2])
 	if err != nil {
-		return "", "", 0, errors.New("Could not decode size")
+		return "", "", 0, errors.New("could not decode size")
 	}
 	return match[1], gzFileExt, size, nil
 }
@@ -304,7 +304,7 @@ func (f *Fs) processEntries(entries fs.DirEntries) (newEntries fs.DirEntries, er
 		case fs.Directory:
 			f.addDir(&newEntries, x)
 		default:
-			return nil, fmt.Errorf("Unknown object type %T", entry)
+			return nil, fmt.Errorf("unknown object type %T", entry)
 		}
 	}
 	return newEntries, nil
@@ -466,10 +466,10 @@ func (f *Fs) rcat(ctx context.Context, dstFileName string, in io.ReadCloser, mod
 		_ = os.Remove(tempFile.Name())
 	}()
 	if err != nil {
-		return nil, fmt.Errorf("Failed to create temporary local FS to spool file: %w", err)
+		return nil, fmt.Errorf("failed to create temporary local FS to spool file: %w", err)
 	}
 	if _, err = io.Copy(tempFile, in); err != nil {
-		return nil, fmt.Errorf("Failed to write temporary local file: %w", err)
+		return nil, fmt.Errorf("failed to write temporary local file: %w", err)
 	}
 	if _, err = tempFile.Seek(0, 0); err != nil {
 		return nil, err
@@ -720,7 +720,7 @@ func (f *Fs) PutStream(ctx context.Context, in io.Reader, src fs.ObjectInfo, opt
 	if found && (oldObj.(*Object).meta.Mode != Uncompressed || compressible) {
 		err = oldObj.(*Object).Object.Remove(ctx)
 		if err != nil {
-			return nil, fmt.Errorf("Could remove original object: %w", err)
+			return nil, fmt.Errorf("couldn't remove original object: %w", err)
 		}
 	}
 
@@ -729,7 +729,7 @@ func (f *Fs) PutStream(ctx context.Context, in io.Reader, src fs.ObjectInfo, opt
 	if compressible {
 		wrapObj, err := operations.Move(ctx, f.Fs, nil, f.dataName(src.Remote(), newObj.size, compressible), newObj.Object)
 		if err != nil {
-			return nil, fmt.Errorf("Couldn't rename streamed Object.: %w", err)
+			return nil, fmt.Errorf("couldn't rename streamed object: %w", err)
 		}
 		newObj.Object = wrapObj
 	}
diff --git a/backend/crypt/cipher.go b/backend/crypt/cipher.go
index 4a3556295..1b265ad19 100644
--- a/backend/crypt/cipher.go
+++ b/backend/crypt/cipher.go
@@ -96,7 +96,7 @@ func NewNameEncryptionMode(s string) (mode NameEncryptionMode, err error) {
 	case "obfuscate":
 		mode = NameEncryptionObfuscated
 	default:
-		err = fmt.Errorf("Unknown file name encryption mode %q", s)
+		err = fmt.Errorf("unknown file name encryption mode %q", s)
 	}
 	return mode, err
 }
@@ -162,7 +162,7 @@ func NewNameEncoding(s string) (enc fileNameEncoding, err error) {
 	case "base32768":
 		enc = base32768.SafeEncoding
 	default:
-		err = fmt.Errorf("Unknown file name encoding mode %q", s)
+		err = fmt.Errorf("unknown file name encoding mode %q", s)
 	}
 	return enc, err
 }
diff --git a/backend/crypt/crypt.go b/backend/crypt/crypt.go
index 11dd55dad..33e57cdb9 100644
--- a/backend/crypt/crypt.go
+++ b/backend/crypt/crypt.go
@@ -328,7 +328,7 @@ func (f *Fs) encryptEntries(ctx context.Context, entries fs.DirEntries) (newEntr
 		case fs.Directory:
 			f.addDir(ctx, &newEntries, x)
 		default:
-			return nil, fmt.Errorf("Unknown object type %T", entry)
+			return nil, fmt.Errorf("unknown object type %T", entry)
 		}
 	}
 	return newEntries, nil
diff --git a/backend/crypt/pkcs7/pkcs7.go b/backend/crypt/pkcs7/pkcs7.go
index db604ae4b..d2a547042 100644
--- a/backend/crypt/pkcs7/pkcs7.go
+++ b/backend/crypt/pkcs7/pkcs7.go
@@ -8,11 +8,11 @@ import "errors"
 
 // Errors Unpad can return
 var (
-	ErrorPaddingNotFound      = errors.New("Bad PKCS#7 padding - not padded")
-	ErrorPaddingNotAMultiple  = errors.New("Bad PKCS#7 padding - not a multiple of blocksize")
-	ErrorPaddingTooLong       = errors.New("Bad PKCS#7 padding - too long")
-	ErrorPaddingTooShort      = errors.New("Bad PKCS#7 padding - too short")
-	ErrorPaddingNotAllTheSame = errors.New("Bad PKCS#7 padding - not all the same")
+	ErrorPaddingNotFound      = errors.New("bad PKCS#7 padding - not padded")
+	ErrorPaddingNotAMultiple  = errors.New("bad PKCS#7 padding - not a multiple of blocksize")
+	ErrorPaddingTooLong       = errors.New("bad PKCS#7 padding - too long")
+	ErrorPaddingTooShort      = errors.New("bad PKCS#7 padding - too short")
+	ErrorPaddingNotAllTheSame = errors.New("bad PKCS#7 padding - not all the same")
 )
 
 // Pad buf using PKCS#7 to a multiple of n.
diff --git a/backend/drive/drive.go b/backend/drive/drive.go
index 9eac37a0e..918faddf9 100644
--- a/backend/drive/drive.go
+++ b/backend/drive/drive.go
@@ -2218,10 +2218,10 @@ func (f *Fs) PutUnchecked(ctx context.Context, in io.Reader, src fs.ObjectInfo,
 
 			exportExt, _, _ = f.findExportFormatByMimeType(ctx, importMimeType)
 			if exportExt == "" {
-				return nil, fmt.Errorf("No export format found for %q", importMimeType)
+				return nil, fmt.Errorf("no export format found for %q", importMimeType)
 			}
 			if exportExt != srcExt && !f.opt.AllowImportNameChange {
-				return nil, fmt.Errorf("Can't convert %q to a document with a different export filetype (%q)", srcExt, exportExt)
+				return nil, fmt.Errorf("can't convert %q to a document with a different export filetype (%q)", srcExt, exportExt)
 			}
 		}
 	}
@@ -2526,7 +2526,7 @@ func (f *Fs) Copy(ctx context.Context, src fs.Object, remote string) (fs.Object,
 // result of List()
 func (f *Fs) Purge(ctx context.Context, dir string) error {
 	if f.opt.TrashedOnly {
-		return errors.New("Can't purge with --drive-trashed-only. Use delete if you want to selectively delete files")
+		return errors.New("can't purge with --drive-trashed-only, use delete if you want to selectively delete files")
 	}
 	return f.purgeCheck(ctx, dir, false)
 }
@@ -3715,7 +3715,7 @@ func (o *baseObject) open(ctx context.Context, url string, options ...fs.OpenOpt
 				url += "acknowledgeAbuse=true"
 				_, res, err = o.httpResponse(ctx, url, "GET", options)
 			} else {
-				err = fmt.Errorf("Use the --drive-acknowledge-abuse flag to download this file: %w", err)
+				err = fmt.Errorf("use the --drive-acknowledge-abuse flag to download this file: %w", err)
 			}
 		}
 		if err != nil {
diff --git a/backend/dropbox/dropbox.go b/backend/dropbox/dropbox.go
index 69d0b4e7d..bcee49821 100644
--- a/backend/dropbox/dropbox.go
+++ b/backend/dropbox/dropbox.go
@@ -1199,7 +1199,7 @@ func (f *Fs) PublicLink(ctx context.Context, remote string, expire fs.Duration,
 			return
 		}
 		if len(listRes.Links) == 0 {
-			err = errors.New("Dropbox says the sharing link already exists, but list came back empty")
+			err = errors.New("sharing link already exists, but list came back empty")
 			return
 		}
 		linkRes = listRes.Links[0]
@@ -1211,7 +1211,7 @@ func (f *Fs) PublicLink(ctx context.Context, remote string, expire fs.Duration,
 		case *sharing.FolderLinkMetadata:
 			link = res.Url
 		default:
-			err = fmt.Errorf("Don't know how to extract link, response has unknown format: %T", res)
+			err = fmt.Errorf("don't know how to extract link, response has unknown format: %T", res)
 		}
 	}
 	return
diff --git a/backend/fichier/api.go b/backend/fichier/api.go
index 15c916c73..1ee812c47 100644
--- a/backend/fichier/api.go
+++ b/backend/fichier/api.go
@@ -487,7 +487,7 @@ func (f *Fs) uploadFile(ctx context.Context, in io.Reader, size int64, fileName,
 	fileName = f.opt.Enc.FromStandardName(fileName)
 
 	if len(uploadID) > 10 || !isAlphaNumeric(uploadID) {
-		return nil, errors.New("Invalid UploadID")
+		return nil, errors.New("invalid UploadID")
 	}
 
 	opts := rest.Opts{
@@ -529,7 +529,7 @@ func (f *Fs) endUpload(ctx context.Context, uploadID string, nodeurl string) (re
 	// fs.Debugf(f, "Ending File Upload `%s`", uploadID)
 
 	if len(uploadID) > 10 || !isAlphaNumeric(uploadID) {
-		return nil, errors.New("Invalid UploadID")
+		return nil, errors.New("invalid UploadID")
 	}
 
 	opts := rest.Opts{
diff --git a/backend/fichier/fichier.go b/backend/fichier/fichier.go
index 8548d00c2..454e391ff 100644
--- a/backend/fichier/fichier.go
+++ b/backend/fichier/fichier.go
@@ -294,7 +294,7 @@ func (f *Fs) NewObject(ctx context.Context, remote string) (fs.Object, error) {
 			path, ok := f.dirCache.GetInv(directoryID)
 
 			if !ok {
-				return nil, errors.New("Cannot find dir in dircache")
+				return nil, errors.New("cannot find dir in dircache")
 			}
 
 			return f.newObjectFromFile(ctx, path, file), nil
diff --git a/backend/ftp/ftp.go b/backend/ftp/ftp.go
index c078f78b0..d92678f08 100644
--- a/backend/ftp/ftp.go
+++ b/backend/ftp/ftp.go
@@ -487,7 +487,7 @@ func NewFs(ctx context.Context, name, root string, m configmap.Mapper) (ff fs.Fs
 		protocol = "ftps://"
 	}
 	if opt.TLS && opt.ExplicitTLS {
-		return nil, errors.New("Implicit TLS and explicit TLS are mutually incompatible. Please revise your config")
+		return nil, errors.New("implicit TLS and explicit TLS are mutually incompatible, please revise your config")
 	}
 	var tlsConfig *tls.Config
 	if opt.TLS || opt.ExplicitTLS {
@@ -718,7 +718,7 @@ func (f *Fs) List(ctx context.Context, dir string) (entries fs.DirEntries, err e
 	case <-timer.C:
 		// if timer fired assume no error but connection dead
 		fs.Errorf(f, "Timeout when waiting for List")
-		return nil, errors.New("Timeout when waiting for List")
+		return nil, errors.New("timeout when waiting for List")
 	}
 
 	// Annoyingly FTP returns success for a directory which
diff --git a/backend/hdfs/fs.go b/backend/hdfs/fs.go
index 8de9ddbac..a68372db6 100644
--- a/backend/hdfs/fs.go
+++ b/backend/hdfs/fs.go
@@ -92,7 +92,7 @@ func NewFs(ctx context.Context, name, root string, m configmap.Mapper) (fs.Fs, e
 	if opt.ServicePrincipalName != "" {
 		options.KerberosClient, err = getKerberosClient()
 		if err != nil {
-			return nil, fmt.Errorf("Problem with kerberos authentication: %s", err)
+			return nil, fmt.Errorf("problem with kerberos authentication: %w", err)
 		}
 		options.KerberosServicePrincipleName = opt.ServicePrincipalName
 
diff --git a/backend/koofr/koofr.go b/backend/koofr/koofr.go
index f77ae019f..f893b898b 100644
--- a/backend/koofr/koofr.go
+++ b/backend/koofr/koofr.go
@@ -351,9 +351,9 @@ func NewFsFromOptions(ctx context.Context, name, root string, opt *Options) (ff
 	}
 	if f.mountID == "" {
 		if opt.MountID == "" {
-			return nil, errors.New("Failed to find primary mount")
+			return nil, errors.New("failed to find primary mount")
 		}
-		return nil, errors.New("Failed to find mount " + opt.MountID)
+		return nil, errors.New("failed to find mount " + opt.MountID)
 	}
 	rootFile, err := f.client.FilesInfo(f.mountID, f.opt.Enc.FromStandardPath("/"+f.root))
 	if err == nil && rootFile.Type != "dir" {
diff --git a/backend/mailru/api/helpers.go b/backend/mailru/api/helpers.go
index 1b43eb182..d7164185f 100644
--- a/backend/mailru/api/helpers.go
+++ b/backend/mailru/api/helpers.go
@@ -16,9 +16,9 @@ import (
 
 // protocol errors
 var (
-	ErrorPrematureEOF  = errors.New("Premature EOF")
-	ErrorInvalidLength = errors.New("Invalid length")
-	ErrorZeroTerminate = errors.New("String must end with zero")
+	ErrorPrematureEOF  = errors.New("premature EOF")
+	ErrorInvalidLength = errors.New("invalid length")
+	ErrorZeroTerminate = errors.New("string must end with zero")
 )
 
 // BinWriter is a binary protocol writer
diff --git a/backend/mailru/mailru.go b/backend/mailru/mailru.go
index 24693c67c..a9a9bab2d 100644
--- a/backend/mailru/mailru.go
+++ b/backend/mailru/mailru.go
@@ -435,10 +435,10 @@ func (f *Fs) authorize(ctx context.Context, force bool) (err error) {
 		t, err = oauthConfig.PasswordCredentialsToken(ctx, f.opt.Username, f.opt.Password)
 	}
 	if err == nil && !tokenIsValid(t) {
-		err = errors.New("Invalid token")
+		err = errors.New("invalid token")
 	}
 	if err != nil {
-		return fmt.Errorf("Failed to authorize: %w", err)
+		return fmt.Errorf("failed to authorize: %w", err)
 	}
 
 	if err = oauthutil.PutToken(f.name, f.m, t, false); err != nil {
@@ -580,7 +580,7 @@ func readBodyWord(res *http.Response) (word string, err error) {
 		word = strings.Split(line, " ")[0]
 	}
 	if word == "" {
-		return "", errors.New("Empty reply from dispatcher")
+		return "", errors.New("empty reply from dispatcher")
 	}
 	return word, nil
 }
@@ -1684,7 +1684,7 @@ func (o *Object) Update(ctx context.Context, in io.Reader, src fs.ObjectInfo, op
 
 			spoolFile, mrHash, err := makeTempFile(ctx, tmpFs, wrapIn, src)
 			if err != nil {
-				return fmt.Errorf("Failed to create spool file: %w", err)
+				return fmt.Errorf("failed to create spool file: %w", err)
 			}
 			if o.putByHash(ctx, mrHash, src, "spool") {
 				// If put by hash is successful, ignore transitive error
@@ -1966,7 +1966,7 @@ func (o *Object) readMetaData(ctx context.Context, force bool) error {
 		return fs.ErrorIsDir
 	}
 	if newObj.remote != o.remote {
-		return fmt.Errorf("File %q path has changed to %q", o.remote, newObj.remote)
+		return fmt.Errorf("file %q path has changed to %q", o.remote, newObj.remote)
 	}
 	o.hasMetaData = true
 	o.size = newObj.size
@@ -2318,7 +2318,7 @@ func (p *serverPool) Dispatch(ctx context.Context, current string) (string, erro
 	})
 	if err != nil || url == "" {
 		closeBody(res)
-		return "", fmt.Errorf("Failed to request file server: %w", err)
+		return "", fmt.Errorf("failed to request file server: %w", err)
 	}
 
 	p.addServer(url, now)
diff --git a/backend/qingstor/qingstor.go b/backend/qingstor/qingstor.go
index 5f5134099..9e9b0c6cc 100644
--- a/backend/qingstor/qingstor.go
+++ b/backend/qingstor/qingstor.go
@@ -253,7 +253,7 @@ func qsServiceConnection(ctx context.Context, opt *Options) (*qs.Service, error)
 		_protocol, _host, _port, err := qsParseEndpoint(endpoint)
 
 		if err != nil {
-			return nil, fmt.Errorf("The endpoint \"%s\" format error", endpoint)
+			return nil, fmt.Errorf("the endpoint \"%s\" format error", endpoint)
 		}
 
 		if _protocol != "" {
diff --git a/backend/qingstor/upload.go b/backend/qingstor/upload.go
index d9a818019..797e718f8 100644
--- a/backend/qingstor/upload.go
+++ b/backend/qingstor/upload.go
@@ -184,7 +184,7 @@ func (u *uploader) upload() error {
 		fs.Debugf(u, "Uploading as single part object to QingStor")
 		return u.singlePartUpload(reader, u.readerPos)
 	} else if err != nil {
-		return fmt.Errorf("read upload data failed: %s", err)
+		return fmt.Errorf("read upload data failed: %w", err)
 	}
 
 	fs.Debugf(u, "Uploading as multi-part object to QingStor")
diff --git a/backend/seafile/seafile.go b/backend/seafile/seafile.go
index 15a708641..ffae61a5a 100644
--- a/backend/seafile/seafile.go
+++ b/backend/seafile/seafile.go
@@ -886,7 +886,7 @@ func (f *Fs) DirMove(ctx context.Context, src fs.Fs, srcRemote, dstRemote string
 	// 1- rename source
 	err = srcFs.renameDir(ctx, srcLibraryID, srcPath, tempName)
 	if err != nil {
-		return fmt.Errorf("Cannot rename source directory to a temporary name: %w", err)
+		return fmt.Errorf("cannot rename source directory to a temporary name: %w", err)
 	}
 
 	// 2- move source to destination
@@ -900,7 +900,7 @@ func (f *Fs) DirMove(ctx context.Context, src fs.Fs, srcRemote, dstRemote string
 	// 3- rename destination back to source name
 	err = f.renameDir(ctx, dstLibraryID, path.Join(dstDir, tempName), dstName)
 	if err != nil {
-		return fmt.Errorf("Cannot rename temporary directory to destination name: %w", err)
+		return fmt.Errorf("cannot rename temporary directory to destination name: %w", err)
 	}
 
 	return nil
@@ -923,7 +923,7 @@ func (f *Fs) Purge(ctx context.Context, dir string) error {
 // CleanUp the trash in the Fs
 func (f *Fs) CleanUp(ctx context.Context) error {
 	if f.libraryName == "" {
-		return errors.New("Cannot clean up at the root of the seafile server: please select a library to clean up")
+		return errors.New("cannot clean up at the root of the seafile server, please select a library to clean up")
 	}
 	libraryID, err := f.getLibraryID(ctx, f.libraryName)
 	if err != nil {
@@ -972,7 +972,7 @@ func (f *Fs) PublicLink(ctx context.Context, remote string, expire fs.Duration,
 	libraryName, filePath := f.splitPath(remote)
 	if libraryName == "" {
 		// We cannot share the whole seafile server, we need at least a library
-		return "", errors.New("Cannot share the root of the seafile server. Please select a library to share")
+		return "", errors.New("cannot share the root of the seafile server, please select a library to share")
 	}
 	libraryID, err := f.getLibraryID(ctx, libraryName)
 	if err != nil {
diff --git a/backend/seafile/webapi.go b/backend/seafile/webapi.go
index 29d2f8645..c1eb33da0 100644
--- a/backend/seafile/webapi.go
+++ b/backend/seafile/webapi.go
@@ -26,7 +26,7 @@ const (
 
 // Errors specific to seafile fs
 var (
-	ErrorInternalDuringUpload = errors.New("Internal server error during file upload")
+	ErrorInternalDuringUpload = errors.New("internal server error during file upload")
 )
 
 // ==================== Seafile API ====================
diff --git a/backend/sftp/sftp.go b/backend/sftp/sftp.go
index 74af5fa41..bb5add94d 100644
--- a/backend/sftp/sftp.go
+++ b/backend/sftp/sftp.go
@@ -515,7 +515,7 @@ func (f *Fs) setEnv(s *ssh.Session) error {
 		// fs.Debugf(f, "Setting env %q = %q", env[:equal], env[equal+1:])
 		err := s.Setenv(env[:equal], env[equal+1:])
 		if err != nil {
-			return fmt.Errorf("Failed to set env var %q: %w", env[:equal], err)
+			return fmt.Errorf("failed to set env var %q: %w", env[:equal], err)
 		}
 	}
 	return nil
diff --git a/backend/swift/swift.go b/backend/swift/swift.go
index 074e2daf7..e4bae345e 100644
--- a/backend/swift/swift.go
+++ b/backend/swift/swift.go
@@ -1303,7 +1303,7 @@ func (o *Object) getSegmentsDlo(ctx context.Context) (segmentsContainer string,
 	}
 	delimiter := strings.Index(dirManifest, "/")
 	if len(dirManifest) == 0 || delimiter < 0 {
-		err = errors.New("Missing or wrong structure of manifest of Dynamic large object")
+		err = errors.New("missing or wrong structure of manifest of Dynamic large object")
 		return
 	}
 	return dirManifest[:delimiter], dirManifest[delimiter+1:], nil
diff --git a/backend/uptobox/uptobox.go b/backend/uptobox/uptobox.go
index 56c4f80a1..e232ac83c 100644
--- a/backend/uptobox/uptobox.go
+++ b/backend/uptobox/uptobox.go
@@ -474,7 +474,7 @@ func (f *Fs) updateFileInformation(ctx context.Context, update *api.UpdateFileIn
 
 func (f *Fs) putUnchecked(ctx context.Context, in io.Reader, remote string, size int64, options ...fs.OpenOption) (fs.Object, error) {
 	if size > int64(200e9) { // max size 200GB
-		return nil, errors.New("File too big, cant upload")
+		return nil, errors.New("file too big, can't upload")
 	} else if size == 0 {
 		return nil, fs.ErrorCantUploadEmptyFiles
 	}
@@ -497,7 +497,7 @@ func (f *Fs) putUnchecked(ctx context.Context, in io.Reader, remote string, size
 		return nil, err
 	}
 	if info.StatusCode != 0 {
-		return nil, fmt.Errorf("putUnchecked: api error: %d - %s", info.StatusCode, info.Message)
+		return nil, fmt.Errorf("putUnchecked api error: %d - %s", info.StatusCode, info.Message)
 	}
 	// we need to have a safe name for the upload to work
 	tmpName := "rcloneTemp" + random.String(8)
@@ -506,7 +506,7 @@ func (f *Fs) putUnchecked(ctx context.Context, in io.Reader, remote string, size
 		return nil, err
 	}
 	if len(upload.Files) != 1 {
-		return nil, errors.New("Upload: unexpected response")
+		return nil, errors.New("upload unexpected response")
 	}
 	match := f.IDRegexp.FindStringSubmatch(upload.Files[0].URL)
 
diff --git a/cmd/cmd.go b/cmd/cmd.go
index 82ae1ad83..5dd120be7 100644
--- a/cmd/cmd.go
+++ b/cmd/cmd.go
@@ -117,7 +117,7 @@ func newFsFileAddFilter(remote string) (fs.Fs, string) {
 	f, fileName := NewFsFile(remote)
 	if fileName != "" {
 		if !fi.InActive() {
-			err := fmt.Errorf("Can't limit to single files when using filters: %v", remote)
+			err := fmt.Errorf("can't limit to single files when using filters: %v", remote)
 			err = fs.CountError(err)
 			log.Fatalf(err.Error())
 		}
diff --git a/cmd/config/config.go b/cmd/config/config.go
index 96734e552..ed5700327 100644
--- a/cmd/config/config.go
+++ b/cmd/config/config.go
@@ -402,7 +402,7 @@ To reconnect use "rclone config reconnect".
 		}
 		err := doDisconnect(context.Background())
 		if err != nil {
-			return fmt.Errorf("Disconnect call failed: %w", err)
+			return fmt.Errorf("disconnect call failed: %w", err)
 		}
 		return nil
 	},
diff --git a/cmd/cryptdecode/cryptdecode.go b/cmd/cryptdecode/cryptdecode.go
index 2f938cbfa..d36c70ca4 100644
--- a/cmd/cryptdecode/cryptdecode.go
+++ b/cmd/cryptdecode/cryptdecode.go
@@ -48,7 +48,7 @@ See the documentation on the [crypt](/crypt/) overlay for more info.
 				return err
 			}
 			if fsInfo.Name != "crypt" {
-				return errors.New("The remote needs to be of type \"crypt\"")
+				return errors.New("the remote needs to be of type \"crypt\"")
 			}
 			cipher, err := crypt.NewCipher(config)
 			if err != nil {
diff --git a/cmd/lsf/lsf.go b/cmd/lsf/lsf.go
index 812edf8ea..732d2b5e8 100644
--- a/cmd/lsf/lsf.go
+++ b/cmd/lsf/lsf.go
@@ -199,7 +199,7 @@ func Lsf(ctx context.Context, fsrc fs.Fs, out io.Writer) error {
 		case 'T':
 			list.AddTier()
 		default:
-			return fmt.Errorf("Unknown format character %q", char)
+			return fmt.Errorf("unknown format character %q", char)
 		}
 	}
 
diff --git a/cmd/mount/dir.go b/cmd/mount/dir.go
index 47ec4bf2d..b82b52179 100644
--- a/cmd/mount/dir.go
+++ b/cmd/mount/dir.go
@@ -199,7 +199,7 @@ func (d *Dir) Rename(ctx context.Context, req *fuse.RenameRequest, newDir fusefs
 	defer log.Trace(d, "oldName=%q, newName=%q, newDir=%+v", req.OldName, req.NewName, newDir)("err=%v", &err)
 	destDir, ok := newDir.(*Dir)
 	if !ok {
-		return fmt.Errorf("Unknown Dir type %T", newDir)
+		return fmt.Errorf("unknown Dir type %T", newDir)
 	}
 
 	err = d.Dir.Rename(req.OldName, req.NewName, destDir.Dir)
diff --git a/cmd/mountlib/check_linux.go b/cmd/mountlib/check_linux.go
index 3cdb34690..1f241af87 100644
--- a/cmd/mountlib/check_linux.go
+++ b/cmd/mountlib/check_linux.go
@@ -22,7 +22,7 @@ const (
 // On Linux we use the OS-specific /proc/mount API so the check won't access the path.
 // Directories marked as "mounted" by autofs are considered not mounted.
 func CheckMountEmpty(mountpoint string) error {
-	const msg = "Directory already mounted, use --allow-non-empty to mount anyway: %s"
+	const msg = "directory already mounted, use --allow-non-empty to mount anyway: %s"
 
 	mountpointAbs, err := filepath.Abs(mountpoint)
 	if err != nil {
diff --git a/cmd/mountlib/check_other.go b/cmd/mountlib/check_other.go
index 0b7eeede7..c8876632c 100644
--- a/cmd/mountlib/check_other.go
+++ b/cmd/mountlib/check_other.go
@@ -17,7 +17,7 @@ import (
 func CheckMountEmpty(mountpoint string) error {
 	fp, err := os.Open(mountpoint)
 	if err != nil {
-		return fmt.Errorf("Can not open: %s: %w", mountpoint, err)
+		return fmt.Errorf("cannot open: %s: %w", mountpoint, err)
 	}
 	defer fs.CheckClose(fp, &err)
 
@@ -26,7 +26,7 @@ func CheckMountEmpty(mountpoint string) error {
 		return nil
 	}
 
-	const msg = "Directory is not empty, use --allow-non-empty to mount anyway: %s"
+	const msg = "directory is not empty, use --allow-non-empty to mount anyway: %s"
 	if err == nil {
 		return fmt.Errorf(msg, mountpoint)
 	}
diff --git a/cmd/rc/rc.go b/cmd/rc/rc.go
index 6b123f97e..53e8697d8 100644
--- a/cmd/rc/rc.go
+++ b/cmd/rc/rc.go
@@ -211,7 +211,7 @@ func doCall(ctx context.Context, path string, in rc.Params) (out rc.Params, err
 			bodyString = err.Error()
 		}
 		bodyString = strings.TrimSpace(bodyString)
-		return nil, fmt.Errorf("Failed to read rc response: %s: %s", resp.Status, bodyString)
+		return nil, fmt.Errorf("failed to read rc response: %s: %s", resp.Status, bodyString)
 	}
 
 	// Parse output
diff --git a/cmd/serve/ftp/ftp.go b/cmd/serve/ftp/ftp.go
index f8ba81725..05f7b0924 100644
--- a/cmd/serve/ftp/ftp.go
+++ b/cmd/serve/ftp/ftp.go
@@ -135,11 +135,11 @@ var passivePortsRe = regexp.MustCompile(`^\s*\d+\s*-\s*\d+\s*$`)
 func newServer(ctx context.Context, f fs.Fs, opt *Options) (*server, error) {
 	host, port, err := net.SplitHostPort(opt.ListenAddr)
 	if err != nil {
-		return nil, errors.New("Failed to parse host:port")
+		return nil, errors.New("failed to parse host:port")
 	}
 	portNum, err := strconv.Atoi(port)
 	if err != nil {
-		return nil, errors.New("Failed to parse host:port")
+		return nil, errors.New("failed to parse host:port")
 	}
 
 	s := &server{
@@ -284,7 +284,7 @@ func (d *Driver) ChangeDir(path string) (err error) {
 		return err
 	}
 	if !n.IsDir() {
-		return errors.New("Not a directory")
+		return errors.New("not a directory")
 	}
 	return nil
 }
@@ -296,12 +296,12 @@ func (d *Driver) ListDir(path string, callback func(ftp.FileInfo) error) (err er
 	defer log.Trace(path, "")("err = %v", &err)
 	node, err := d.vfs.Stat(path)
 	if err == vfs.ENOENT {
-		return errors.New("Directory not found")
+		return errors.New("directory not found")
 	} else if err != nil {
 		return err
 	}
 	if !node.IsDir() {
-		return errors.New("Not a directory")
+		return errors.New("not a directory")
 	}
 
 	dir := node.(*vfs.Dir)
@@ -335,7 +335,7 @@ func (d *Driver) DeleteDir(path string) (err error) {
 		return err
 	}
 	if !node.IsDir() {
-		return errors.New("Not a directory")
+		return errors.New("not a directory")
 	}
 	err = node.Remove()
 	if err != nil {
@@ -354,7 +354,7 @@ func (d *Driver) DeleteFile(path string) (err error) {
 		return err
 	}
 	if !node.IsFile() {
-		return errors.New("Not a file")
+		return errors.New("not a file")
 	}
 	err = node.Remove()
 	if err != nil {
@@ -392,12 +392,12 @@ func (d *Driver) GetFile(path string, offset int64) (size int64, fr io.ReadClose
 	node, err := d.vfs.Stat(path)
 	if err == vfs.ENOENT {
 		fs.Infof(path, "File not found")
-		return 0, nil, errors.New("File not found")
+		return 0, nil, errors.New("file not found")
 	} else if err != nil {
 		return 0, nil, err
 	}
 	if !node.IsFile() {
-		return 0, nil, errors.New("Not a file")
+		return 0, nil, errors.New("not a file")
 	}
 
 	handle, err := node.Open(os.O_RDONLY)
@@ -426,7 +426,7 @@ func (d *Driver) PutFile(path string, data io.Reader, appendData bool) (n int64,
 	if err == nil {
 		isExist = true
 		if node.IsDir() {
-			return 0, errors.New("A dir has the same name")
+			return 0, errors.New("a dir has the same name")
 		}
 	} else {
 		if os.IsNotExist(err) {
diff --git a/cmd/serve/restic/restic.go b/cmd/serve/restic/restic.go
index a8eb7b483..7139b084b 100644
--- a/cmd/serve/restic/restic.go
+++ b/cmd/serve/restic/restic.go
@@ -139,7 +139,7 @@ with a path of ` + "`/<username>/`" + `.
 			s := NewServer(f, &httpflags.Opt)
 			if stdio {
 				if terminal.IsTerminal(int(os.Stdout.Fd())) {
-					return errors.New("Refusing to run HTTP2 server directly on a terminal, please let restic start rclone")
+					return errors.New("refusing to run HTTP2 server directly on a terminal, please let restic start rclone")
 				}
 
 				conn := &StdioConn{
diff --git a/cmd/serve/sftp/connection.go b/cmd/serve/sftp/connection.go
index 693b5fbb0..d8be2bce5 100644
--- a/cmd/serve/sftp/connection.go
+++ b/cmd/serve/sftp/connection.go
@@ -74,7 +74,7 @@ func (c *conn) execCommand(ctx context.Context, out io.Writer, command string) (
 		}
 		usage, err := about(ctx)
 		if err != nil {
-			return fmt.Errorf("About failed: %w", err)
+			return fmt.Errorf("about failed: %w", err)
 		}
 		total, used, free := int64(-1), int64(-1), int64(-1)
 		if usage.Total != nil {
diff --git a/cmd/settier/settier.go b/cmd/settier/settier.go
index 97953727a..6be1c1c6a 100644
--- a/cmd/settier/settier.go
+++ b/cmd/settier/settier.go
@@ -47,7 +47,7 @@ Or just provide remote directory and all files in directory will be tiered
 		cmd.Run(false, false, command, func() error {
 			isSupported := fsrc.Features().SetTier
 			if !isSupported {
-				return fmt.Errorf("Remote %s does not support settier", fsrc.Name())
+				return fmt.Errorf("remote %s does not support settier", fsrc.Name())
 			}
 
 			return operations.SetTier(context.Background(), fsrc, tier)
diff --git a/cmd/tree/tree.go b/cmd/tree/tree.go
index 4bd899462..2528d9dc2 100644
--- a/cmd/tree/tree.go
+++ b/cmd/tree/tree.go
@@ -102,7 +102,7 @@ For a more interactive navigation of the remote see the
 			var err error
 			outFile, err = os.Create(outFileName)
 			if err != nil {
-				return fmt.Errorf("failed to create output file: %v", err)
+				return fmt.Errorf("failed to create output file: %w", err)
 			}
 		}
 		opts.VerSort = opts.VerSort || sort == "version"
@@ -209,7 +209,7 @@ func (dirs Fs) Stat(filePath string) (fi os.FileInfo, err error) {
 	}
 	_, entry := dirtree.DirTree(dirs).Find(filePath)
 	if entry == nil {
-		return nil, fmt.Errorf("Couldn't find %q in directory cache", filePath)
+		return nil, fmt.Errorf("couldn't find %q in directory cache", filePath)
 	}
 	return &FileInfo{entry}, nil
 }
@@ -221,7 +221,7 @@ func (dirs Fs) ReadDir(dir string) (names []string, err error) {
 	dir = strings.TrimLeft(dir, "/")
 	entries, ok := dirs[dir]
 	if !ok {
-		return nil, fmt.Errorf("Couldn't find directory %q", dir)
+		return nil, fmt.Errorf("couldn't find directory %q", dir)
 	}
 	for _, entry := range entries {
 		names = append(names, path.Base(entry.Remote()))
diff --git a/fs/accounting/accounting.go b/fs/accounting/accounting.go
index 53d6549fb..a019232fb 100644
--- a/fs/accounting/accounting.go
+++ b/fs/accounting/accounting.go
@@ -19,7 +19,7 @@ import (
 
 // ErrorMaxTransferLimitReached defines error when transfer limit is reached.
 // Used for checking on exit and matching to correct exit code.
-var ErrorMaxTransferLimitReached = errors.New("Max transfer limit reached as set by --max-transfer")
+var ErrorMaxTransferLimitReached = errors.New("max transfer limit reached as set by --max-transfer")
 
 // ErrorMaxTransferLimitReachedFatal is returned from Read when the max
 // transfer limit is reached.
diff --git a/fs/config/configfile/configfile.go b/fs/config/configfile/configfile.go
index df01f25a5..e9c498995 100644
--- a/fs/config/configfile/configfile.go
+++ b/fs/config/configfile/configfile.go
@@ -106,7 +106,7 @@ func (s *Storage) Save() error {
 
 	configPath := config.GetConfigPath()
 	if configPath == "" {
-		return fmt.Errorf("Failed to save config file: Path is empty")
+		return fmt.Errorf("failed to save config file, path is empty")
 	}
 
 	dir, name := filepath.Split(configPath)
@@ -116,18 +116,18 @@ func (s *Storage) Save() error {
 	}
 	f, err := ioutil.TempFile(dir, name)
 	if err != nil {
-		return fmt.Errorf("Failed to create temp file for new config: %v", err)
+		return fmt.Errorf("failed to create temp file for new config: %w", err)
 	}
 	defer func() {
 		_ = f.Close()
 		if err := os.Remove(f.Name()); err != nil && !os.IsNotExist(err) {
-			fs.Errorf(nil, "Failed to remove temp config file: %v", err)
+			fs.Errorf(nil, "failed to remove temp config file: %v", err)
 		}
 	}()
 
 	var buf bytes.Buffer
 	if err := goconfig.SaveConfigData(s.gc, &buf); err != nil {
-		return fmt.Errorf("Failed to save config file: %v", err)
+		return fmt.Errorf("failed to save config file: %w", err)
 	}
 
 	if err := config.Encrypt(&buf, f); err != nil {
@@ -137,7 +137,7 @@ func (s *Storage) Save() error {
 	_ = f.Sync()
 	err = f.Close()
 	if err != nil {
-		return fmt.Errorf("Failed to close config file: %v", err)
+		return fmt.Errorf("failed to close config file: %w", err)
 	}
 
 	var fileMode os.FileMode = 0600
@@ -157,10 +157,10 @@ func (s *Storage) Save() error {
 	}
 
 	if err = os.Rename(configPath, configPath+".old"); err != nil && !os.IsNotExist(err) {
-		return fmt.Errorf("Failed to move previous config to backup location: %v", err)
+		return fmt.Errorf("failed to move previous config to backup location: %w", err)
 	}
 	if err = os.Rename(f.Name(), configPath); err != nil {
-		return fmt.Errorf("Failed to move newly written config from %s to final location: %v", f.Name(), err)
+		return fmt.Errorf("failed to move newly written config from %s to final location: %v", f.Name(), err)
 	}
 	if err := os.Remove(configPath + ".old"); err != nil && !os.IsNotExist(err) {
 		fs.Errorf(nil, "Failed to remove backup config file: %v", err)
@@ -177,7 +177,7 @@ func (s *Storage) Serialize() (string, error) {
 	s.check()
 	var buf bytes.Buffer
 	if err := goconfig.SaveConfigData(s.gc, &buf); err != nil {
-		return "", fmt.Errorf("Failed to save config file: %v", err)
+		return "", fmt.Errorf("failed to save config file: %w", err)
 	}
 
 	return buf.String(), nil
diff --git a/fs/config/crypt.go b/fs/config/crypt.go
index 002e6c49f..6792811dc 100644
--- a/fs/config/crypt.go
+++ b/fs/config/crypt.go
@@ -133,7 +133,7 @@ func Decrypt(b io.ReadSeeker) (io.Reader, error) {
 		return nil, fmt.Errorf("failed to load base64 encoded data: %w", err)
 	}
 	if len(box) < 24+secretbox.Overhead {
-		return nil, errors.New("Configuration data too short")
+		return nil, errors.New("configuration data too short")
 	}
 
 	var out []byte
@@ -206,7 +206,7 @@ func Encrypt(src io.Reader, dst io.Writer) error {
 	enc := base64.NewEncoder(base64.StdEncoding, dst)
 	_, err := enc.Write(nonce[:])
 	if err != nil {
-		return fmt.Errorf("Failed to write config file: %v", err)
+		return fmt.Errorf("failed to write config file: %w", err)
 	}
 
 	var key [32]byte
@@ -219,7 +219,7 @@ func Encrypt(src io.Reader, dst io.Writer) error {
 	b := secretbox.Seal(nil, data, &nonce, &key)
 	_, err = enc.Write(b)
 	if err != nil {
-		return fmt.Errorf("Failed to write config file: %v", err)
+		return fmt.Errorf("failed to write config file: %w", err)
 	}
 	return enc.Close()
 }
diff --git a/fs/cutoffmode.go b/fs/cutoffmode.go
index a58c5c452..9f6390663 100644
--- a/fs/cutoffmode.go
+++ b/fs/cutoffmode.go
@@ -38,7 +38,7 @@ func (m *CutoffMode) Set(s string) error {
 			return nil
 		}
 	}
-	return fmt.Errorf("Unknown cutoff mode %q", s)
+	return fmt.Errorf("unknown cutoff mode %q", s)
 }
 
 // Type of the value
@@ -50,7 +50,7 @@ func (m *CutoffMode) Type() string {
 func (m *CutoffMode) UnmarshalJSON(in []byte) error {
 	return UnmarshalJSONFlag(in, m, func(i int64) error {
 		if i < 0 || i >= int64(len(cutoffModeToString)) {
-			return fmt.Errorf("Out of range cutoff mode %d", i)
+			return fmt.Errorf("out of range cutoff mode %d", i)
 		}
 		*m = (CutoffMode)(i)
 		return nil
diff --git a/fs/dump.go b/fs/dump.go
index f0c72bcab..a15671253 100644
--- a/fs/dump.go
+++ b/fs/dump.go
@@ -78,7 +78,7 @@ func (f *DumpFlags) Set(s string) error {
 			}
 		}
 		if !found {
-			return fmt.Errorf("Unknown dump flag %q", part)
+			return fmt.Errorf("unknown dump flag %q", part)
 		}
 	}
 	*f = flags
diff --git a/fs/dump_test.go b/fs/dump_test.go
index c0ea248dd..ede6125e8 100644
--- a/fs/dump_test.go
+++ b/fs/dump_test.go
@@ -30,7 +30,7 @@ func TestDumpFlagsSet(t *testing.T) {
 		{"bodies,headers,auth", DumpBodies | DumpHeaders | DumpAuth, ""},
 		{"bodies,headers,auth", DumpBodies | DumpHeaders | DumpAuth, ""},
 		{"headers,bodies,requests,responses,auth,filters", DumpHeaders | DumpBodies | DumpRequests | DumpResponses | DumpAuth | DumpFilters, ""},
-		{"headers,bodies,unknown,auth", 0, "Unknown dump flag \"unknown\""},
+		{"headers,bodies,unknown,auth", 0, "unknown dump flag \"unknown\""},
 	} {
 		f := DumpFlags(-1)
 		initial := f
@@ -69,7 +69,7 @@ func TestDumpFlagsUnmarshallJSON(t *testing.T) {
 		{`"bodies,headers,auth"`, DumpBodies | DumpHeaders | DumpAuth, ""},
 		{`"bodies,headers,auth"`, DumpBodies | DumpHeaders | DumpAuth, ""},
 		{`"headers,bodies,requests,responses,auth,filters"`, DumpHeaders | DumpBodies | DumpRequests | DumpResponses | DumpAuth | DumpFilters, ""},
-		{`"headers,bodies,unknown,auth"`, 0, "Unknown dump flag \"unknown\""},
+		{`"headers,bodies,unknown,auth"`, 0, "unknown dump flag \"unknown\""},
 		{`0`, DumpFlags(0), ""},
 		{strconv.Itoa(int(DumpBodies)), DumpBodies, ""},
 		{strconv.Itoa(int(DumpBodies | DumpHeaders | DumpAuth)), DumpBodies | DumpHeaders | DumpAuth, ""},
diff --git a/fs/filter/filter.go b/fs/filter/filter.go
index e35018fa5..741580fff 100644
--- a/fs/filter/filter.go
+++ b/fs/filter/filter.go
@@ -199,7 +199,7 @@ func NewFilter(opt *Opt) (f *Filter, err error) {
 
 	for _, rule := range f.Opt.FilesFrom {
 		if !inActive {
-			return nil, fmt.Errorf("The usage of --files-from overrides all other filters, it should be used alone or with --files-from-raw")
+			return nil, fmt.Errorf("the usage of --files-from overrides all other filters, it should be used alone or with --files-from-raw")
 		}
 		f.initAddFile() // init to show --files-from set even if no files within
 		err := forEachLine(rule, false, func(line string) error {
@@ -214,7 +214,7 @@ func NewFilter(opt *Opt) (f *Filter, err error) {
 		// --files-from-raw can be used with --files-from, hence we do
 		// not need to get the value of f.InActive again
 		if !inActive {
-			return nil, fmt.Errorf("The usage of --files-from-raw overrides all other filters, it should be used alone or with --files-from")
+			return nil, fmt.Errorf("the usage of --files-from-raw overrides all other filters, it should be used alone or with --files-from")
 		}
 		f.initAddFile() // init to show --files-from set even if no files within
 		err := forEachLine(rule, true, func(line string) error {
diff --git a/fs/filter/filter_test.go b/fs/filter/filter_test.go
index 81a01af3d..27da120c4 100644
--- a/fs/filter/filter_test.go
+++ b/fs/filter/filter_test.go
@@ -62,7 +62,7 @@ func TestNewFilterForbiddenMixOfFilesFromAndFilterRule(t *testing.T) {
 
 	_, err := NewFilter(&Opt)
 	require.Error(t, err)
-	require.Contains(t, err.Error(), "The usage of --files-from overrides all other filters")
+	require.Contains(t, err.Error(), "the usage of --files-from overrides all other filters")
 }
 
 func TestNewFilterForbiddenMixOfFilesFromRawAndFilterRule(t *testing.T) {
@@ -85,7 +85,7 @@ func TestNewFilterForbiddenMixOfFilesFromRawAndFilterRule(t *testing.T) {
 
 	_, err := NewFilter(&Opt)
 	require.Error(t, err)
-	require.Contains(t, err.Error(), "The usage of --files-from-raw overrides all other filters")
+	require.Contains(t, err.Error(), "the usage of --files-from-raw overrides all other filters")
 }
 
 func TestNewFilterWithFilesFromAlone(t *testing.T) {
diff --git a/fs/hash/hash.go b/fs/hash/hash.go
index 48ecdcd4c..93b1de3b2 100644
--- a/fs/hash/hash.go
+++ b/fs/hash/hash.go
@@ -153,7 +153,7 @@ func (h *Type) Set(s string) error {
 		*h = hash.hashType
 		return nil
 	}
-	return fmt.Errorf("Unknown hash type %q", s)
+	return fmt.Errorf("unknown hash type %q", s)
 }
 
 // Type of the value
diff --git a/fs/log.go b/fs/log.go
index 423352344..8328b9106 100644
--- a/fs/log.go
+++ b/fs/log.go
@@ -61,7 +61,7 @@ func (l *LogLevel) Set(s string) error {
 			return nil
 		}
 	}
-	return fmt.Errorf("Unknown log level %q", s)
+	return fmt.Errorf("unknown log level %q", s)
 }
 
 // Type of the value
@@ -73,7 +73,7 @@ func (l *LogLevel) Type() string {
 func (l *LogLevel) UnmarshalJSON(in []byte) error {
 	return UnmarshalJSONFlag(in, l, func(i int64) error {
 		if i < 0 || i >= int64(LogLevel(len(logLevelToString))) {
-			return fmt.Errorf("Unknown log level %d", i)
+			return fmt.Errorf("unknown log level %d", i)
 		}
 		*l = (LogLevel)(i)
 		return nil
diff --git a/fs/open_options.go b/fs/open_options.go
index 938e38d04..e357a9a69 100644
--- a/fs/open_options.go
+++ b/fs/open_options.go
@@ -72,28 +72,28 @@ func (o *RangeOption) Header() (key string, value string) {
 func ParseRangeOption(s string) (po *RangeOption, err error) {
 	const preamble = "bytes="
 	if !strings.HasPrefix(s, preamble) {
-		return nil, errors.New("Range: header invalid: doesn't start with " + preamble)
+		return nil, errors.New("range: header invalid: doesn't start with " + preamble)
 	}
 	s = s[len(preamble):]
 	if strings.ContainsRune(s, ',') {
-		return nil, errors.New("Range: header invalid: contains multiple ranges which isn't supported")
+		return nil, errors.New("range: header invalid: contains multiple ranges which isn't supported")
 	}
 	dash := strings.IndexRune(s, '-')
 	if dash < 0 {
-		return nil, errors.New("Range: header invalid: contains no '-'")
+		return nil, errors.New("range: header invalid: contains no '-'")
 	}
 	start, end := strings.TrimSpace(s[:dash]), strings.TrimSpace(s[dash+1:])
 	o := RangeOption{Start: -1, End: -1}
 	if start != "" {
 		o.Start, err = strconv.ParseInt(start, 10, 64)
 		if err != nil || o.Start < 0 {
-			return nil, errors.New("Range: header invalid: bad start")
+			return nil, errors.New("range: header invalid: bad start")
 		}
 	}
 	if end != "" {
 		o.End, err = strconv.ParseInt(end, 10, 64)
 		if err != nil || o.End < 0 {
-			return nil, errors.New("Range: header invalid: bad end")
+			return nil, errors.New("range: header invalid: bad end")
 		}
 	}
 	return &o, nil
diff --git a/fs/operations/check.go b/fs/operations/check.go
index a7a52e299..5cb3b0cf9 100644
--- a/fs/operations/check.go
+++ b/fs/operations/check.go
@@ -80,7 +80,7 @@ func (c *checkMarch) DstOnly(dst fs.DirEntry) (recurse bool) {
 		if c.opt.OneWay {
 			return false
 		}
-		err := fmt.Errorf("File not in %v", c.opt.Fsrc)
+		err := fmt.Errorf("file not in %v", c.opt.Fsrc)
 		fs.Errorf(dst, "%v", err)
 		_ = fs.CountError(err)
 		atomic.AddInt32(&c.differences, 1)
@@ -102,7 +102,7 @@ func (c *checkMarch) DstOnly(dst fs.DirEntry) (recurse bool) {
 func (c *checkMarch) SrcOnly(src fs.DirEntry) (recurse bool) {
 	switch src.(type) {
 	case fs.Object:
-		err := fmt.Errorf("File not in %v", c.opt.Fdst)
+		err := fmt.Errorf("file not in %v", c.opt.Fdst)
 		fs.Errorf(src, "%v", err)
 		_ = fs.CountError(err)
 		atomic.AddInt32(&c.differences, 1)
@@ -125,7 +125,7 @@ func (c *checkMarch) checkIdentical(ctx context.Context, dst, src fs.Object) (di
 		tr.Done(ctx, err)
 	}()
 	if sizeDiffers(ctx, src, dst) {
-		err = fmt.Errorf("Sizes differ")
+		err = fmt.Errorf("sizes differ")
 		fs.Errorf(src, "%v", err)
 		return true, false, nil
 	}
@@ -424,7 +424,7 @@ func CheckSum(ctx context.Context, fsrc, fsum fs.Fs, sumFile string, hashType ha
 			continue
 		}
 		// filesystem missed the file, sum wasn't consumed
-		err := fmt.Errorf("File not in %v", opt.Fdst)
+		err := fmt.Errorf("file not in %v", opt.Fdst)
 		fs.Errorf(filename, "%v", err)
 		_ = fs.CountError(err)
 		if lastErr == nil {
diff --git a/fs/operations/lsjson.go b/fs/operations/lsjson.go
index 5af5a4295..144a47bb6 100644
--- a/fs/operations/lsjson.go
+++ b/fs/operations/lsjson.go
@@ -122,7 +122,7 @@ func newListJSON(ctx context.Context, fsrc fs.Fs, remote string, opt *ListJSONOp
 			return nil, fmt.Errorf("ListJSON failed to load config for crypt remote: %w", err)
 		}
 		if fsInfo.Name != "crypt" {
-			return nil, errors.New("The remote needs to be of type \"crypt\"")
+			return nil, errors.New("the remote needs to be of type \"crypt\"")
 		}
 		lj.cipher, err = crypt.NewCipher(config)
 		if err != nil {
diff --git a/fs/operations/operations.go b/fs/operations/operations.go
index 5eccc44f7..bdeeaf036 100644
--- a/fs/operations/operations.go
+++ b/fs/operations/operations.go
@@ -1407,7 +1407,7 @@ func Rcat(ctx context.Context, fdst fs.Fs, dstFileName string, in io.ReadCloser,
 		fs.Debugf(fdst, "Target remote doesn't support streaming uploads, creating temporary local FS to spool file")
 		tmpLocalFs, err := fs.TemporaryLocalFs(ctx)
 		if err != nil {
-			return nil, fmt.Errorf("Failed to create temporary local FS to spool file: %w", err)
+			return nil, fmt.Errorf("failed to create temporary local FS to spool file: %w", err)
 		}
 		defer func() {
 			err := Purge(ctx, tmpLocalFs, "")
@@ -1523,7 +1523,7 @@ func GetCompareDest(ctx context.Context) (CompareDest []fs.Fs, err error) {
 	ci := fs.GetConfig(ctx)
 	CompareDest, err = cache.GetArr(ctx, ci.CompareDest)
 	if err != nil {
-		return nil, fserrors.FatalError(fmt.Errorf("Failed to make fs for --compare-dest %q: %v", ci.CompareDest, err))
+		return nil, fserrors.FatalError(fmt.Errorf("failed to make fs for --compare-dest %q: %w", ci.CompareDest, err))
 	}
 	return CompareDest, nil
 }
@@ -1562,7 +1562,7 @@ func GetCopyDest(ctx context.Context, fdst fs.Fs) (CopyDest []fs.Fs, err error)
 	ci := fs.GetConfig(ctx)
 	CopyDest, err = cache.GetArr(ctx, ci.CopyDest)
 	if err != nil {
-		return nil, fserrors.FatalError(fmt.Errorf("Failed to make fs for --copy-dest %q: %v", ci.CopyDest, err))
+		return nil, fserrors.FatalError(fmt.Errorf("failed to make fs for --copy-dest %q: %w", ci.CopyDest, err))
 	}
 	if !SameConfigArr(fdst, CopyDest) {
 		return nil, fserrors.FatalError(errors.New("parameter to --copy-dest has to be on the same remote as destination"))
@@ -1777,7 +1777,7 @@ func copyURLFn(ctx context.Context, dstFileName string, url string, autoFilename
 			_, params, err := mime.ParseMediaType(resp.Header.Get("Content-Disposition"))
 			headerFilename := path.Base(strings.Replace(params["filename"], "\\", "/", -1))
 			if err != nil || headerFilename == "" {
-				return fmt.Errorf("copyurl failed: filename not found in the Content-Dispoition header")
+				return fmt.Errorf("CopyURL failed: filename not found in the Content-Dispoition header")
 			}
 			fs.Debugf(headerFilename, "filename found in Content-Disposition header.")
 			return fn(ctx, headerFilename, resp.Body, resp.ContentLength, modTime)
@@ -1822,7 +1822,7 @@ func BackupDir(ctx context.Context, fdst fs.Fs, fsrc fs.Fs, srcFileName string)
 	if ci.BackupDir != "" {
 		backupDir, err = cache.Get(ctx, ci.BackupDir)
 		if err != nil {
-			return nil, fserrors.FatalError(fmt.Errorf("Failed to make fs for --backup-dir %q: %v", ci.BackupDir, err))
+			return nil, fserrors.FatalError(fmt.Errorf("failed to make fs for --backup-dir %q: %w", ci.BackupDir, err))
 		}
 		if !SameConfig(fdst, backupDir) {
 			return nil, fserrors.FatalError(errors.New("parameter to --backup-dir has to be on the same remote as destination"))
diff --git a/fs/operations/operations_test.go b/fs/operations/operations_test.go
index 04b26e8b8..02a44d385 100644
--- a/fs/operations/operations_test.go
+++ b/fs/operations/operations_test.go
@@ -1696,7 +1696,7 @@ func TestCopyFileMaxTransfer(t *testing.T) {
 	accounting.Stats(ctx).ResetCounters()
 	err = operations.CopyFile(ctx, r.Fremote, r.Flocal, file2.Path, file2.Path)
 	require.NotNil(t, err, "Did not get expected max transfer limit error")
-	assert.Contains(t, err.Error(), "Max transfer limit reached")
+	assert.Contains(t, err.Error(), "max transfer limit reached")
 	assert.True(t, fserrors.IsFatalError(err), fmt.Sprintf("Not fatal error: %v: %#v:", err, err))
 	r.CheckLocalItems(t, file1, file2, file3, file4)
 	r.CheckRemoteItems(t, file1)
@@ -1708,7 +1708,7 @@ func TestCopyFileMaxTransfer(t *testing.T) {
 	accounting.Stats(ctx).ResetCounters()
 	err = operations.CopyFile(ctx, r.Fremote, r.Flocal, file3.Path, file3.Path)
 	require.NotNil(t, err)
-	assert.Contains(t, err.Error(), "Max transfer limit reached")
+	assert.Contains(t, err.Error(), "max transfer limit reached")
 	assert.True(t, fserrors.IsNoRetryError(err))
 	r.CheckLocalItems(t, file1, file2, file3, file4)
 	r.CheckRemoteItems(t, file1)
diff --git a/fs/rc/internal.go b/fs/rc/internal.go
index 10077ae09..24e67eabb 100644
--- a/fs/rc/internal.go
+++ b/fs/rc/internal.go
@@ -475,7 +475,7 @@ func rcRunCommand(ctx context.Context, in Params) (out Params, err error) {
 		cmd.Stdout = httpResponse
 		cmd.Stderr = httpResponse
 	} else {
-		return nil, fmt.Errorf("Unknown returnType %q", returnType)
+		return nil, fmt.Errorf("unknown returnType %q", returnType)
 	}
 
 	err = cmd.Run()
diff --git a/fs/rc/rcserver/rcserver_test.go b/fs/rc/rcserver/rcserver_test.go
index f75cfe52f..34181b631 100644
--- a/fs/rc/rcserver/rcserver_test.go
+++ b/fs/rc/rcserver/rcserver_test.go
@@ -497,7 +497,7 @@ func TestRCWithAuth(t *testing.T) {
 		ContentType: "application/x-www-form-urlencoded",
 		Status:      http.StatusInternalServerError,
 		Expected: `{
-	"error": "Unknown returnType \"POTATO\"",
+	"error": "unknown returnType \"POTATO\"",
 	"input": {
 		"command": "version",
 		"returnType": "POTATO"
diff --git a/fs/rc/webgui/webgui.go b/fs/rc/webgui/webgui.go
index ea37382ee..8153024d1 100644
--- a/fs/rc/webgui/webgui.go
+++ b/fs/rc/webgui/webgui.go
@@ -63,7 +63,7 @@ func CheckAndDownloadWebGUIRelease(checkUpdate bool, forceUpdate bool, fetchURL
 	// Get the latest release details
 	WebUIURL, tag, size, err := GetLatestReleaseURL(fetchURL)
 	if err != nil {
-		return fmt.Errorf("Error checking for web gui release update, skipping update: %w", err)
+		return fmt.Errorf("error checking for web gui release update, skipping update: %w", err)
 	}
 	dat, err := ioutil.ReadFile(tagPath)
 	tagsMatch := false
diff --git a/fs/sync/sync.go b/fs/sync/sync.go
index 58e74e22a..052b867e8 100644
--- a/fs/sync/sync.go
+++ b/fs/sync/sync.go
@@ -825,7 +825,7 @@ func (s *syncCopyMove) tryRename(src fs.Object) bool {
 
 // errorMaxDurationReached defines error when transfer duration is reached
 // Used for checking on exit and matching to correct exit code.
-var errorMaxDurationReached = fserrors.FatalError(errors.New("Max transfer duration reached as set by --max-duration"))
+var errorMaxDurationReached = fserrors.FatalError(errors.New("max transfer duration reached as set by --max-duration"))
 
 // Syncs fsrc into fdst
 //
diff --git a/fstest/mockobject/mockobject.go b/fstest/mockobject/mockobject.go
index 0d0c4516c..084536b85 100644
--- a/fstest/mockobject/mockobject.go
+++ b/fstest/mockobject/mockobject.go
@@ -140,7 +140,7 @@ func (o *ContentMockObject) Open(ctx context.Context, options ...fs.OpenOption)
 			offset, limit = x.Decode(size)
 		default:
 			if option.Mandatory() {
-				return nil, fmt.Errorf("Unsupported mandatory option: %v", option)
+				return nil, fmt.Errorf("unsupported mandatory option: %v", option)
 			}
 		}
 	}
diff --git a/fstest/test_all/clean.go b/fstest/test_all/clean.go
index c12a4839a..6da23b7e1 100644
--- a/fstest/test_all/clean.go
+++ b/fstest/test_all/clean.go
@@ -56,7 +56,7 @@ func cleanFs(ctx context.Context, remote string, cleanup bool) error {
 			}
 			err = operations.Purge(ctx, dir, "")
 			if err != nil {
-				err = fmt.Errorf("Purge failed: %w", err)
+				err = fmt.Errorf("purge failed: %w", err)
 				lastErr = err
 				fs.Errorf(dir, "%v", err)
 				return nil
diff --git a/lib/http/http.go b/lib/http/http.go
index ac5befd37..1ff7c1148 100644
--- a/lib/http/http.go
+++ b/lib/http/http.go
@@ -122,7 +122,7 @@ func useSSL(opt Options) bool {
 func NewServer(listeners, tlsListeners []net.Listener, opt Options) (Server, error) {
 	// Validate input
 	if len(listeners) == 0 && len(tlsListeners) == 0 {
-		return nil, errors.New("Can't create server without listeners")
+		return nil, errors.New("can't create server without listeners")
 	}
 
 	// Prepare TLS config
@@ -130,12 +130,12 @@ func NewServer(listeners, tlsListeners []net.Listener, opt Options) (Server, err
 
 	useSSL := useSSL(opt)
 	if (len(opt.SslCertBody) > 0) != (len(opt.SslKeyBody) > 0) {
-		err := errors.New("Need both SslCertBody and SslKeyBody to use SSL")
+		err := errors.New("need both SslCertBody and SslKeyBody to use SSL")
 		log.Fatalf(err.Error())
 		return nil, err
 	}
 	if (opt.SslCert != "") != (opt.SslKey != "") {
-		err := errors.New("Need both -cert and -key to use SSL")
+		err := errors.New("need both -cert and -key to use SSL")
 		log.Fatalf(err.Error())
 		return nil, err
 	}
@@ -156,12 +156,12 @@ func NewServer(listeners, tlsListeners []net.Listener, opt Options) (Server, err
 			Certificates: []tls.Certificate{cert},
 		}
 	} else if len(listeners) == 0 && len(tlsListeners) != 0 {
-		return nil, errors.New("No SslKey or non-tlsListeners")
+		return nil, errors.New("no SslKey or non-tlsListeners")
 	}
 
 	if opt.ClientCA != "" {
 		if !useSSL {
-			err := errors.New("Can't use --client-ca without --cert and --key")
+			err := errors.New("can't use --client-ca without --cert and --key")
 			log.Fatalf(err.Error())
 			return nil, err
 		}
@@ -172,7 +172,7 @@ func NewServer(listeners, tlsListeners []net.Listener, opt Options) (Server, err
 			return nil, err
 		}
 		if !certpool.AppendCertsFromPEM(pem) {
-			err := errors.New("Can't parse client certificate authority")
+			err := errors.New("can't parse client certificate authority")
 			log.Fatalf(err.Error())
 			return nil, err
 		}
diff --git a/lib/jwtutil/jwtutil.go b/lib/jwtutil/jwtutil.go
index 8473c45bd..af99ed3f8 100644
--- a/lib/jwtutil/jwtutil.go
+++ b/lib/jwtutil/jwtutil.go
@@ -78,7 +78,7 @@ func Config(id, name string, claims *jws.ClaimSet, header *jws.Header, queryPara
 	result := &response{}
 	err = json.NewDecoder(strings.NewReader(s)).Decode(result)
 	if result.AccessToken == "" && err == nil {
-		err = errors.New("No AccessToken in Response")
+		err = errors.New("no AccessToken in Response")
 	}
 	if err != nil {
 		return fmt.Errorf("jwtutil: failed to get token: %w", err)
diff --git a/lib/rest/url.go b/lib/rest/url.go
index 4a1d71390..8f443d59d 100644
--- a/lib/rest/url.go
+++ b/lib/rest/url.go
@@ -11,7 +11,7 @@ import (
 func URLJoin(base *url.URL, path string) (*url.URL, error) {
 	rel, err := url.Parse(path)
 	if err != nil {
-		return nil, fmt.Errorf("Error parsing %q as URL: %w", path, err)
+		return nil, fmt.Errorf("error parsing %q as URL: %w", path, err)
 	}
 	return base.ResolveReference(rel), nil
 }
diff --git a/vfs/file.go b/vfs/file.go
index 4c4fc214a..2d3199f13 100644
--- a/vfs/file.go
+++ b/vfs/file.go
@@ -400,7 +400,7 @@ func (f *File) _applyPendingModTime() error {
 	defer func() { f.pendingModTime = time.Time{} }()
 
 	if f.o == nil {
-		return errors.New("Cannot apply ModTime, file object is not available")
+		return errors.New("cannot apply ModTime, file object is not available")
 	}
 
 	dt := f.pendingModTime.Sub(f.o.ModTime(context.Background()))
diff --git a/vfs/vfscommon/cachemode.go b/vfs/vfscommon/cachemode.go
index a7f35fe9c..a2d91bd4e 100644
--- a/vfs/vfscommon/cachemode.go
+++ b/vfs/vfscommon/cachemode.go
@@ -40,7 +40,7 @@ func (l *CacheMode) Set(s string) error {
 			return nil
 		}
 	}
-	return fmt.Errorf("Unknown cache mode level %q", s)
+	return fmt.Errorf("unknown cache mode level %q", s)
 }
 
 // Type of the value
@@ -52,7 +52,7 @@ func (l *CacheMode) Type() string {
 func (l *CacheMode) UnmarshalJSON(in []byte) error {
 	return fs.UnmarshalJSONFlag(in, l, func(i int64) error {
 		if i < 0 || i >= int64(len(cacheModeToString)) {
-			return fmt.Errorf("Unknown cache mode level %d", i)
+			return fmt.Errorf("unknown cache mode level %d", i)
 		}
 		*l = CacheMode(i)
 		return nil
diff --git a/vfs/vfsflags/filemode.go b/vfs/vfsflags/filemode.go
index 50a8bc423..b1c2e8bcd 100644
--- a/vfs/vfsflags/filemode.go
+++ b/vfs/vfsflags/filemode.go
@@ -20,7 +20,7 @@ func (x *FileMode) String() string {
 func (x *FileMode) Set(s string) error {
 	i, err := strconv.ParseInt(s, 8, 64)
 	if err != nil {
-		return fmt.Errorf("Bad FileMode - must be octal digits: %w", err)
+		return fmt.Errorf("bad FileMode - must be octal digits: %w", err)
 	}
 	*x.Mode = (os.FileMode)(i)
 	return nil