diff --git a/backend/local/local.go b/backend/local/local.go
index 99c9c6f0f..65782308f 100644
--- a/backend/local/local.go
+++ b/backend/local/local.go
@@ -569,9 +569,8 @@ func (f *Fs) PutStream(ctx context.Context, in io.Reader, src fs.ObjectInfo, opt
 
 // Mkdir creates the directory if it doesn't exist
 func (f *Fs) Mkdir(ctx context.Context, dir string) error {
-	// FIXME: https://github.com/syncthing/syncthing/blob/master/lib/osutil/mkdirall_windows.go
 	localPath := f.localPath(dir)
-	err := os.MkdirAll(localPath, 0777)
+	err := file.MkdirAll(localPath, 0777)
 	if err != nil {
 		return err
 	}
@@ -765,7 +764,7 @@ func (f *Fs) DirMove(ctx context.Context, src fs.Fs, srcRemote, dstRemote string
 
 	// Create parent of destination
 	dstParentPath := filepath.Dir(dstPath)
-	err = os.MkdirAll(dstParentPath, 0777)
+	err = file.MkdirAll(dstParentPath, 0777)
 	if err != nil {
 		return err
 	}
@@ -1099,7 +1098,7 @@ func (o *Object) Open(ctx context.Context, options ...fs.OpenOption) (in io.Read
 // mkdirAll makes all the directories needed to store the object
 func (o *Object) mkdirAll() error {
 	dir := filepath.Dir(o.path)
-	return os.MkdirAll(dir, 0777)
+	return file.MkdirAll(dir, 0777)
 }
 
 type nopWriterCloser struct {
diff --git a/cmd/copy/copy.go b/cmd/copy/copy.go
index 887024450..ba2815852 100644
--- a/cmd/copy/copy.go
+++ b/cmd/copy/copy.go
@@ -78,6 +78,7 @@ recently very efficiently like this:
 **Note**: Use the |--dry-run| or the |--interactive|/|-i| flag to test without copying anything.
 `, "|", "`"),
 	Run: func(command *cobra.Command, args []string) {
+
 		cmd.CheckArgs(2, 2, command, args)
 		fsrc, srcFileName, fdst := cmd.NewFsSrcFileDst(args)
 		cmd.Run(true, true, command, func() error {
diff --git a/cmd/gendocs/gendocs.go b/cmd/gendocs/gendocs.go
index 91b80929a..fda7d55a4 100644
--- a/cmd/gendocs/gendocs.go
+++ b/cmd/gendocs/gendocs.go
@@ -13,6 +13,7 @@ import (
 	"time"
 
 	"github.com/rclone/rclone/cmd"
+	"github.com/rclone/rclone/lib/file"
 	"github.com/spf13/cobra"
 	"github.com/spf13/cobra/doc"
 	"github.com/spf13/pflag"
@@ -55,7 +56,7 @@ rclone.org website.`,
 		// Create the directory structure
 		root := args[0]
 		out := filepath.Join(root, "commands")
-		err := os.MkdirAll(out, 0777)
+		err := file.MkdirAll(out, 0777)
 		if err != nil {
 			return err
 		}
diff --git a/cmd/selfupdate/selfupdate_test.go b/cmd/selfupdate/selfupdate_test.go
index 2e6b15b58..b8c52a349 100644
--- a/cmd/selfupdate/selfupdate_test.go
+++ b/cmd/selfupdate/selfupdate_test.go
@@ -16,6 +16,7 @@ import (
 
 	"github.com/rclone/rclone/fs"
 	"github.com/rclone/rclone/fstest/testy"
+	"github.com/rclone/rclone/lib/file"
 	"github.com/rclone/rclone/lib/random"
 	"github.com/stretchr/testify/assert"
 )
@@ -52,7 +53,7 @@ func makeTestDir() (testDir string, err error) {
 
 	for attempt := 0; attempt < maxAttempts; attempt++ {
 		testDir = testDirBase + random.String(4)
-		err = os.MkdirAll(testDir, os.ModePerm)
+		err = file.MkdirAll(testDir, os.ModePerm)
 		if err == nil {
 			break
 		}
diff --git a/cmd/serve/docker/docker_test.go b/cmd/serve/docker/docker_test.go
index 0a8f99b76..169fd6e70 100644
--- a/cmd/serve/docker/docker_test.go
+++ b/cmd/serve/docker/docker_test.go
@@ -20,6 +20,7 @@ import (
 	"github.com/rclone/rclone/fs"
 	"github.com/rclone/rclone/fs/config"
 	"github.com/rclone/rclone/fstest"
+	"github.com/rclone/rclone/lib/file"
 
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -36,7 +37,7 @@ func initialise(ctx context.Context, t *testing.T) (string, fs.Fs) {
 	// Make test cache directory
 	testDir, err := fstest.LocalRemote()
 	require.NoError(t, err)
-	err = os.MkdirAll(testDir, 0755)
+	err = file.MkdirAll(testDir, 0755)
 	require.NoError(t, err)
 
 	// Make test file system
@@ -350,7 +351,7 @@ func testMountAPI(t *testing.T, sockAddr string) {
 
 	// Run test sequence
 	path1 := filepath.Join(testDir, "path1")
-	require.NoError(t, os.MkdirAll(path1, 0755))
+	require.NoError(t, file.MkdirAll(path1, 0755))
 	mount1 := filepath.Join(testDir, "vol1")
 	res := ""
 
diff --git a/cmd/serve/docker/driver.go b/cmd/serve/docker/driver.go
index 1d1fcefdf..14970958f 100644
--- a/cmd/serve/docker/driver.go
+++ b/cmd/serve/docker/driver.go
@@ -19,6 +19,7 @@ import (
 	"github.com/rclone/rclone/fs"
 	"github.com/rclone/rclone/fs/config"
 	"github.com/rclone/rclone/lib/atexit"
+	"github.com/rclone/rclone/lib/file"
 	"github.com/rclone/rclone/vfs/vfscommon"
 	"github.com/rclone/rclone/vfs/vfsflags"
 )
@@ -44,12 +45,12 @@ func NewDriver(ctx context.Context, root string, mntOpt *mountlib.Options, vfsOp
 	if err != nil {
 		return nil, errors.Wrap(err, "failed to make --cache-dir absolute")
 	}
-	err = os.MkdirAll(cacheDir, 0700)
+	err = file.MkdirAll(cacheDir, 0700)
 	if err != nil {
 		return nil, errors.Wrapf(err, "failed to create cache directory: %s", cacheDir)
 	}
 
-	//err = os.MkdirAll(root, 0755)
+	//err = file.MkdirAll(root, 0755)
 	if err != nil {
 		return nil, errors.Wrapf(err, "failed to create mount root: %s", root)
 	}
diff --git a/cmd/serve/docker/serve.go b/cmd/serve/docker/serve.go
index 63c5f8d2a..94a1ce45b 100644
--- a/cmd/serve/docker/serve.go
+++ b/cmd/serve/docker/serve.go
@@ -13,6 +13,7 @@ import (
 
 	"github.com/rclone/rclone/fs"
 	"github.com/rclone/rclone/lib/atexit"
+	"github.com/rclone/rclone/lib/file"
 )
 
 // Server connects plugin with docker daemon by protocol
@@ -87,7 +88,7 @@ func writeSpecFile(addr, proto, specDir string) (string, error) {
 	if specDir == "" {
 		specDir = defSpecDir
 	}
-	if err := os.MkdirAll(specDir, 0755); err != nil {
+	if err := file.MkdirAll(specDir, 0755); err != nil {
 		return "", err
 	}
 	specFile := filepath.Join(specDir, "rclone.spec")
diff --git a/cmd/serve/docker/unix.go b/cmd/serve/docker/unix.go
index 696f8d4f7..3c533d454 100644
--- a/cmd/serve/docker/unix.go
+++ b/cmd/serve/docker/unix.go
@@ -8,6 +8,8 @@ import (
 	"net"
 	"os"
 	"path/filepath"
+
+	"github.com/rclone/rclone/lib/file"
 )
 
 func newUnixListener(path string, gid int) (net.Listener, string, error) {
@@ -31,7 +33,7 @@ func newUnixListener(path string, gid int) (net.Listener, string, error) {
 		path = filepath.Join(sockDir, path)
 	}
 
-	if err := os.MkdirAll(filepath.Dir(path), 0755); err != nil {
+	if err := file.MkdirAll(filepath.Dir(path), 0755); err != nil {
 		return nil, "", err
 	}
 	if err := os.Remove(path); err != nil && !os.IsNotExist(err) {
diff --git a/cmd/serve/docker/volume.go b/cmd/serve/docker/volume.go
index fd37d5211..770a5f893 100644
--- a/cmd/serve/docker/volume.go
+++ b/cmd/serve/docker/volume.go
@@ -14,6 +14,7 @@ import (
 	"github.com/rclone/rclone/fs"
 	"github.com/rclone/rclone/fs/config"
 	"github.com/rclone/rclone/fs/rc"
+	"github.com/rclone/rclone/lib/file"
 )
 
 // Errors
@@ -153,7 +154,7 @@ func (vol *Volume) checkMountpoint() error {
 	}
 	_, err := os.Lstat(path)
 	if os.IsNotExist(err) {
-		if err = os.MkdirAll(path, 0700); err != nil {
+		if err = file.MkdirAll(path, 0700); err != nil {
 			return errors.Wrapf(err, "failed to create mountpoint: %s", path)
 		}
 	} else if err != nil {
diff --git a/cmd/serve/sftp/server.go b/cmd/serve/sftp/server.go
index 178169714..a6ba3802d 100644
--- a/cmd/serve/sftp/server.go
+++ b/cmd/serve/sftp/server.go
@@ -25,6 +25,7 @@ import (
 	"github.com/rclone/rclone/fs"
 	"github.com/rclone/rclone/fs/config"
 	"github.com/rclone/rclone/lib/env"
+	"github.com/rclone/rclone/lib/file"
 	"github.com/rclone/rclone/vfs"
 	"github.com/rclone/rclone/vfs/vfsflags"
 	"golang.org/x/crypto/ssh"
@@ -227,7 +228,7 @@ func (s *server) serve() (err error) {
 		if err != nil && len(s.opt.HostKeys) == 0 {
 			fs.Debugf(nil, "Failed to load %q: %v", keyPath, err)
 			// If loading a cached key failed, make the keys and retry
-			err = os.MkdirAll(cachePath, 0700)
+			err = file.MkdirAll(cachePath, 0700)
 			if err != nil {
 				return errors.Wrap(err, "failed to create cache path")
 			}
diff --git a/cmd/test/makefiles/makefiles.go b/cmd/test/makefiles/makefiles.go
index 4edaebf07..08d1e3ccd 100644
--- a/cmd/test/makefiles/makefiles.go
+++ b/cmd/test/makefiles/makefiles.go
@@ -14,6 +14,7 @@ import (
 	"github.com/rclone/rclone/cmd/test"
 	"github.com/rclone/rclone/fs"
 	"github.com/rclone/rclone/fs/config/flags"
+	"github.com/rclone/rclone/lib/file"
 	"github.com/rclone/rclone/lib/random"
 	"github.com/spf13/cobra"
 )
@@ -134,7 +135,7 @@ func (d *dir) list(path string, output []string) []string {
 
 // writeFile writes a random file at dir/name
 func writeFile(dir, name string) int64 {
-	err := os.MkdirAll(dir, 0777)
+	err := file.MkdirAll(dir, 0777)
 	if err != nil {
 		log.Fatalf("Failed to make directory %q: %v", dir, err)
 	}
diff --git a/fs/config/config.go b/fs/config/config.go
index 0bded3ee2..b1c7a51d9 100644
--- a/fs/config/config.go
+++ b/fs/config/config.go
@@ -275,7 +275,7 @@ func makeConfigPath() string {
 			return configFile
 		}
 		var mkdirErr error
-		if mkdirErr = os.MkdirAll(configDir, os.ModePerm); mkdirErr == nil {
+		if mkdirErr = file.MkdirAll(configDir, os.ModePerm); mkdirErr == nil {
 			return configFile
 		}
 		// Problem: Try a fallback location. If we did find a home directory then
diff --git a/fs/config/configfile/configfile.go b/fs/config/configfile/configfile.go
index f1eb79ba6..6b93d4943 100644
--- a/fs/config/configfile/configfile.go
+++ b/fs/config/configfile/configfile.go
@@ -13,6 +13,7 @@ import (
 	"github.com/pkg/errors"
 	"github.com/rclone/rclone/fs"
 	"github.com/rclone/rclone/fs/config"
+	"github.com/rclone/rclone/lib/file"
 )
 
 // Install installs the config file handler
@@ -109,7 +110,7 @@ func (s *Storage) Save() error {
 	}
 
 	dir, name := filepath.Split(configPath)
-	err := os.MkdirAll(dir, os.ModePerm)
+	err := file.MkdirAll(dir, os.ModePerm)
 	if err != nil {
 		return errors.Wrap(err, "failed to create config directory")
 	}
diff --git a/fs/rc/webgui/webgui.go b/fs/rc/webgui/webgui.go
index 39ee5d9c1..a272d73e6 100644
--- a/fs/rc/webgui/webgui.go
+++ b/fs/rc/webgui/webgui.go
@@ -17,6 +17,7 @@ import (
 
 	"github.com/pkg/errors"
 	"github.com/rclone/rclone/fs"
+	"github.com/rclone/rclone/lib/file"
 )
 
 // GetLatestReleaseURL returns the latest release details of the rclone-webui-react
@@ -95,7 +96,7 @@ func CheckAndDownloadWebGUIRelease(checkUpdate bool, forceUpdate bool, fetchURL
 
 		cachePathExist, cachePathStat, _ := exists(cachePath)
 		if !cachePathExist {
-			if err := os.MkdirAll(cachePath, 0755); err != nil {
+			if err := file.MkdirAll(cachePath, 0755); err != nil {
 				return errors.New("Error creating cache directory: " + cachePath)
 			}
 		}
@@ -174,7 +175,7 @@ func Unzip(src, dest string) (err error) {
 	}
 	defer fs.CheckClose(r, &err)
 
-	if err := os.MkdirAll(dest, 0755); err != nil {
+	if err := file.MkdirAll(dest, 0755); err != nil {
 		return err
 	}
 
@@ -193,14 +194,14 @@ func Unzip(src, dest string) (err error) {
 		defer fs.CheckClose(rc, &err)
 
 		if f.FileInfo().IsDir() {
-			if err := os.MkdirAll(path, 0755); err != nil {
+			if err := file.MkdirAll(path, 0755); err != nil {
 				return err
 			}
 		} else {
-			if err := os.MkdirAll(filepath.Dir(path), 0755); err != nil {
+			if err := file.MkdirAll(filepath.Dir(path), 0755); err != nil {
 				return err
 			}
-			f, err := os.OpenFile(path, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
+			f, err := file.OpenFile(path, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
 			if err != nil {
 				return err
 			}
@@ -239,7 +240,7 @@ func exists(path string) (existence bool, stat os.FileInfo, err error) {
 func CreatePathIfNotExist(path string) (err error) {
 	exists, stat, _ := exists(path)
 	if !exists {
-		if err := os.MkdirAll(path, 0755); err != nil {
+		if err := file.MkdirAll(path, 0755); err != nil {
 			return errors.New("Error creating : " + path)
 		}
 	}
diff --git a/fstest/run.go b/fstest/run.go
index 8e99b3f89..70c396d69 100644
--- a/fstest/run.go
+++ b/fstest/run.go
@@ -44,6 +44,7 @@ import (
 	"github.com/rclone/rclone/fs/hash"
 	"github.com/rclone/rclone/fs/object"
 	"github.com/rclone/rclone/fs/walk"
+	"github.com/rclone/rclone/lib/file"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -212,7 +213,7 @@ func (r *Run) WriteFile(filePath, content string, t time.Time) Item {
 	// FIXME make directories?
 	filePath = path.Join(r.LocalName, filePath)
 	dirPath := path.Dir(filePath)
-	err := os.MkdirAll(dirPath, 0770)
+	err := file.MkdirAll(dirPath, 0770)
 	if err != nil {
 		r.Fatalf("Failed to make directories %q: %v", dirPath, err)
 	}
diff --git a/fstest/test_all/report.go b/fstest/test_all/report.go
index 03ca3a518..bcc1b5658 100644
--- a/fstest/test_all/report.go
+++ b/fstest/test_all/report.go
@@ -15,6 +15,7 @@ import (
 	"time"
 
 	"github.com/rclone/rclone/fs"
+	"github.com/rclone/rclone/lib/file"
 	"github.com/skratchdot/open-golang/open"
 )
 
@@ -75,7 +76,7 @@ func NewReport() *Report {
 
 	// Create output directory for logs and report
 	r.LogDir = path.Join(*outputDir, r.DateTime)
-	err = os.MkdirAll(r.LogDir, 0777)
+	err = file.MkdirAll(r.LogDir, 0777)
 	if err != nil {
 		log.Fatalf("Failed to make log directory: %v", err)
 	}
diff --git a/lib/file/mkdir_other.go b/lib/file/mkdir_other.go
new file mode 100644
index 000000000..9f49826a2
--- /dev/null
+++ b/lib/file/mkdir_other.go
@@ -0,0 +1,11 @@
+//go:build !windows
+// +build !windows
+
+package file
+
+import "os"
+
+// MkdirAll just calls os.MkdirAll on non-Windows.
+func MkdirAll(path string, perm os.FileMode) error {
+	return os.MkdirAll(path, perm)
+}
diff --git a/lib/file/mkdir_windows.go b/lib/file/mkdir_windows.go
new file mode 100644
index 000000000..36ccadd9c
--- /dev/null
+++ b/lib/file/mkdir_windows.go
@@ -0,0 +1,77 @@
+//go:build windows
+// +build windows
+
+package file
+
+import (
+	"os"
+	"path/filepath"
+	"syscall"
+)
+
+// MkdirAll creates a directory named path, along with any necessary parents.
+//
+// Improves os.MkdirAll by avoiding trying to create a folder \\? when the
+// volume of a given extended length path does not exist.
+//
+// Based on source code from golang's os.MkdirAll
+// (https://github.com/golang/go/blob/master/src/os/path.go)
+func MkdirAll(path string, perm os.FileMode) error {
+	// Fast path: if we can tell whether path is a directory or file, stop with success or error.
+	dir, err := os.Stat(path)
+	if err == nil {
+		if dir.IsDir() {
+			return nil
+		}
+		return &os.PathError{
+			Op:   "mkdir",
+			Path: path,
+			Err:  syscall.ENOTDIR,
+		}
+	}
+
+	// Slow path: make sure parent exists and then call Mkdir for path.
+	i := len(path)
+	for i > 0 && os.IsPathSeparator(path[i-1]) { // Skip trailing path separator.
+		i--
+	}
+	if i > 0 {
+		path = path[:i]
+
+		if path == filepath.VolumeName(path) {
+			// Make reference to a drive's root directory include the trailing slash.
+			// In extended-length form without trailing slash ("\\?\C:"), os.Stat
+			// and os.Mkdir both fails. With trailing slash ("\\?\C:\") works,
+			// and regular paths with or without it ("C:" and "C:\") both works.
+			path = path + string(os.PathSeparator)
+		} else {
+			// See if there is a parent to be created first.
+			// Not when path refer to a drive's root directory, because we don't
+			// want to return noninformative error trying to create \\?.
+			j := i
+			for j > 0 && !os.IsPathSeparator(path[j-1]) { // Scan backward over element.
+				j--
+			}
+			if j > 1 {
+				// Create parent.
+				err = MkdirAll(path[:j-1], perm)
+				if err != nil {
+					return err
+				}
+			}
+		}
+	}
+
+	// Parent now exists; invoke Mkdir and use its result.
+	err = os.Mkdir(path, perm)
+	if err != nil {
+		// Handle arguments like "foo/." by
+		// double-checking that directory doesn't exist.
+		dir, err1 := os.Lstat(path)
+		if err1 == nil && dir.IsDir() {
+			return nil
+		}
+		return err
+	}
+	return nil
+}
diff --git a/lib/file/mkdir_windows_test.go b/lib/file/mkdir_windows_test.go
new file mode 100644
index 000000000..9342f3c2e
--- /dev/null
+++ b/lib/file/mkdir_windows_test.go
@@ -0,0 +1,132 @@
+//go:build windows
+// +build windows
+
+package file
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+// Basic test from golang's os/path_test.go
+func TestMkdirAll(t *testing.T) {
+	tmpDir, tidy := testDir(t)
+	defer tidy()
+
+	path := tmpDir + "/dir/./dir2"
+	err := MkdirAll(path, 0777)
+	if err != nil {
+		t.Fatalf("MkdirAll %q: %s", path, err)
+	}
+
+	// Already exists, should succeed.
+	err = MkdirAll(path, 0777)
+	if err != nil {
+		t.Fatalf("MkdirAll %q (second time): %s", path, err)
+	}
+
+	// Make file.
+	fpath := path + "/file"
+	f, err := Create(fpath)
+	if err != nil {
+		t.Fatalf("create %q: %s", fpath, err)
+	}
+	defer f.Close()
+
+	// Can't make directory named after file.
+	err = MkdirAll(fpath, 0777)
+	if err == nil {
+		t.Fatalf("MkdirAll %q: no error", fpath)
+	}
+	perr, ok := err.(*os.PathError)
+	if !ok {
+		t.Fatalf("MkdirAll %q returned %T, not *PathError", fpath, err)
+	}
+	if filepath.Clean(perr.Path) != filepath.Clean(fpath) {
+		t.Fatalf("MkdirAll %q returned wrong error path: %q not %q", fpath, filepath.Clean(perr.Path), filepath.Clean(fpath))
+	}
+
+	// Can't make subdirectory of file.
+	ffpath := fpath + "/subdir"
+	err = MkdirAll(ffpath, 0777)
+	if err == nil {
+		t.Fatalf("MkdirAll %q: no error", ffpath)
+	}
+	perr, ok = err.(*os.PathError)
+	if !ok {
+		t.Fatalf("MkdirAll %q returned %T, not *PathError", ffpath, err)
+	}
+	if filepath.Clean(perr.Path) != filepath.Clean(fpath) {
+		t.Fatalf("MkdirAll %q returned wrong error path: %q not %q", ffpath, filepath.Clean(perr.Path), filepath.Clean(fpath))
+	}
+
+	path = tmpDir + `\dir\.\dir2\`
+	err = MkdirAll(path, 0777)
+	if err != nil {
+		t.Fatalf("MkdirAll %q: %s", path, err)
+	}
+}
+
+func unusedDrive(t *testing.T) string {
+	letter := FindUnusedDriveLetter()
+	require.NotEqual(t, letter, 0)
+	return string(letter) + ":"
+}
+
+func checkMkdirAll(t *testing.T, path string, valid bool, errormsg string) {
+	if valid {
+		assert.NoError(t, MkdirAll(path, 0777))
+	} else {
+		err := MkdirAll(path, 0777)
+		assert.Error(t, err)
+		assert.Equal(t, errormsg, err.Error())
+	}
+}
+
+func checkMkdirAllSubdirs(t *testing.T, path string, valid bool, errormsg string) {
+	checkMkdirAll(t, path, valid, errormsg)
+	checkMkdirAll(t, path+`\`, valid, errormsg)
+	checkMkdirAll(t, path+`\parent`, valid, errormsg)
+	checkMkdirAll(t, path+`\parent\`, valid, errormsg)
+	checkMkdirAll(t, path+`\parent\child`, valid, errormsg)
+	checkMkdirAll(t, path+`\parent\child\`, valid, errormsg)
+}
+
+// Testing paths on existing drive
+func TestMkdirAllOnDrive(t *testing.T) {
+	path, tidy := testDir(t)
+	defer tidy()
+
+	dir, err := os.Stat(path)
+	require.NoError(t, err)
+	require.True(t, dir.IsDir())
+
+	drive := filepath.VolumeName(path)
+
+	checkMkdirAll(t, drive, true, "")
+	checkMkdirAll(t, drive+`\`, true, "")
+	checkMkdirAll(t, `\\?\`+drive, true, "")
+	checkMkdirAll(t, `\\?\`+drive+`\`, true, "")
+	checkMkdirAllSubdirs(t, path, true, "")
+	checkMkdirAllSubdirs(t, `\\?\`+path, true, "")
+}
+
+// Testing paths on unused drive
+// This is where there is a difference from golang's os.MkdirAll. It would
+// recurse extended-length paths down to the "\\?" prefix and return the
+// noninformative error:
+// "mkdir \\?: The filename, directory name, or volume label syntax is incorrect."
+// Our version stops the recursion at drive's root directory, and reports:
+// "mkdir \\?\A:\: The system cannot find the path specified."
+func TestMkdirAllOnUnusedDrive(t *testing.T) {
+	path := unusedDrive(t)
+	errormsg := fmt.Sprintf("mkdir %s\\: The system cannot find the path specified.", path)
+	checkMkdirAllSubdirs(t, path, false, errormsg)
+	errormsg = fmt.Sprintf("mkdir \\\\?\\%s\\: The system cannot find the path specified.", path)
+	checkMkdirAllSubdirs(t, `\\?\`+path, false, errormsg)
+}
diff --git a/vfs/test_vfs/test_vfs.go b/vfs/test_vfs/test_vfs.go
index 9d6f3168e..bd11ac02c 100644
--- a/vfs/test_vfs/test_vfs.go
+++ b/vfs/test_vfs/test_vfs.go
@@ -296,7 +296,7 @@ func main() {
 		log.Fatalf("%s: Syntax [opts] <directory>", os.Args[0])
 	}
 	dir := args[0]
-	_ = os.MkdirAll(dir, 0777)
+	_ = file.MkdirAll(dir, 0777)
 
 	var (
 		wg   sync.WaitGroup
diff --git a/vfs/vfscache/cache.go b/vfs/vfscache/cache.go
index 48efc0490..c12d5c409 100644
--- a/vfs/vfscache/cache.go
+++ b/vfs/vfscache/cache.go
@@ -150,7 +150,7 @@ func New(ctx context.Context, fremote fs.Fs, opt *vfscommon.Options, avFn AddVir
 
 // createDir creates a directory path, along with any necessary parents
 func createDir(dir string) error {
-	return os.MkdirAll(dir, 0700)
+	return file.MkdirAll(dir, 0700)
 }
 
 // createRootDir creates a single cache root directory