I'm having the exact same issue, here's all my content:
Error: Fatal error: failed to mount FUSE fs: mountpoint directory is at root: Z:\
Command: rclone mount Freydrive: Z:\Freydrive --vfs-cache-mode full --no-modtime --fast-list -vv --log-file=rclone.log
Where Freydrive: is a remote teamshare GDrive (however this issue also occurs with a SFTP remote so seems indiscriminate of remote type).
This error also occurs when doing a plain rclone mount Freydrive: Z:\Freydrive so the other flags don't seem to affect it.
The directory Z:\Freydrive does not exist, in fact the entire Z: mountpoint is nonexistent when running the command.
However, if I tried for example C:\Freydrive (where the Freydrive folder does not exist, but the C:\ drive does exist), the same error occurs.
I'm using the latest stable rclone - version v1.54.0, os windows/amd64, go1.15.7
The latest WinFSP is installed - version 1.8.20304.
My config is encrypted so I don't believe I can post it, but it just includes 2x GDrive teamdrive remotes (one of which is Freydrive), both using my own client_id/secret, and 1x SFTP remote. The error occurs with all of them. Other operations seem to work on them; I can list the root dir of the teamdrives without issue.
The full log file is as follows: https://pastebin.com/DxCMJZ46
Don't remember atm, if there was a good reason why I left it commented out. Perhaps was just afraid it would break somewhere I had not tested it properly. But anyway, seems the real issue is something else:
Edit: Didn't notice at first @ncw mentioning the docs section:
The following examples will mount to an automatically assigned drive, to specific drive letter X: , to path C:\path\to\nonexistent\directory (which must be non-existent subdirectory of an existing parent directory or drive
So yes, mounting "C:\potato" is not legal according to this. But then I'm surprised it was possible before. I see the old docs said more or less the same:
Or on Windows like this where + "X:" + is an unused drive letter
or use a path to non-existent directory.
rclone + commandName + remote:path/to/files X:
rclone + commandName + remote:path/to/files C:\path\to\nonexistent\directory
So then what @klunky says means the docs were wrong before also: it did in reality not have to be non-existent.
Mounting to dir on non-existant drive does not work:
rclone mount remote: Z:\Mnt
Cannot create WinFsp-FUSE file system: invalid mount point.
2021/02/08 13:34:40 ERROR : jottacloud root '': Mount failed
2021/02/08 13:34:40 Fatal error: failed to mount FUSE fs: mount stopped before calling Init: mount failed
No. To get this to work we need to change code and release a new version, unfortunately!
I will see if i can get a pull request to fix this case quite soon.
But I think the following one is not supposed to work, and did not before 1.54, when Z: does not exist:
Thanks for your amazing work on this guys! Is there any way to mount to a dir on a non-existent drive though? I was hoping to mount multiple remotes under different folders on the same non-existent drive (Z:). Would there be any way to do this?
That is not possible, you would have to use a workaround such as the one described above. The WinFsp library rclone on Windows is based on uses Windows mechanisms DefineDosDevice for drive mounting and NTFS reparse points (of type directory junction) for mounting on a directory path, and neither of them allow this.