diff --git a/vfs/help.go b/vfs/help.go
index 67758f42e..b068f88e8 100644
--- a/vfs/help.go
+++ b/vfs/help.go
@@ -110,6 +110,13 @@ for two reasons.  Firstly because it is only checked every
 !--vfs-cache-poll-interval!.  Secondly because open files cannot be
 evicted from the cache.
 
+You **should not** run two copies of rclone using the same VFS cache
+with the same or overlapping remotes if using !--vfs-cache-mode > off!.
+This can potentially cause data corruption if you do. You can work
+around this by giving each rclone its own cache hierarchy with
+!--cache-dir!. You don't need to worry about this if the remotes in
+use don't overlap.
+
 #### --vfs-cache-mode off
 
 In this mode (the default) the cache will read directly from the remote and write