Drive letter not available - how to fix?

I asked this question a couple months ago, but I want to try again.

An odd variation on an old theme. VeraCrypt assigns a user-selected drive letter to a file (or something) when mounting an encrypted "VeraCrypt container". It has a function to automatically dismount the drive when the signs off, issues a "Lock", or when the computer goes to sleep, but this function stopped working for me a couple years ago. To compensate, I defined a task that issues a VeraCrypt Dismount command under those conditions. (I barely know anything about defining task triggers so I very well may be doing it wrong.) Anyway, my task almost works. When I log back in VeraCrypt no longer has the drive mounted ... according to VeraCrypt. However, Windows still has the drive letter in use. If I click on the drive letter in File Explorer I get a popup saying "M:\ is unavailable".

I could just give up on M: and have VereCrypt assign a different drive letter, but I've got scripts expecting M: to be the drive in question.

The drive does not show in a Subst display - whether or not VeraCrypt has the drive allocated - so I can't use Subst to free it.

The previous advice I got was to wait until I can reboot, but this is happening often enough that I'd rather have a less disruptive technique. Is there one?

I know nothing about Veracrypt but I would like to suggest you include the word Veracrypt in the title to drawn the attention of those in the know about it.

glasskuter said:

I know nothing about Veracrypt but I would like to suggest you include the word Veracrypt in the title to drawn the attention of those in the know about it.

Click to expand...

I don't see an "Edit" button. How do I change the title (or any other part of my posting)?
But actually, I don't think my question directly relates to VeraCrypt. A VeraCrypt bug may have resulted in the partially dismounted drive, but once I've got a partially dismounted drive (for whatever reason) I need to fix it.

BTW, the allocating a drive letter to some "virtual" drive is not limited to VeraCrypt. Macrium Reflect also does that when "mounting" a backup. So did Acronis True Image back when I was using it. Those mounted drives also don't show in a Subst display. (But they don't get hung half way through a dismount.)

There may be some restriction in the forum that the title can't be changed after the thread has been responded to.
Sorry, if I led you astray.

I would try option 3 or 5 in this tutorial

I tried the option 3 you mentioned shortly before reading your reply. I unfortunately get the error "The system cannot find the file specified."
I hadn't tried option 5, but it also fails. The first step - issuing "get-partition" doesn't list the partially mounted drive so I can go no further.

Hey @Ghot @zbook do you or any other of you hardware guys have any suggestions for this poter?

See if this software allows you to identify and free drive letters:

zbook said:

See if this software allows you to identify and free drive letters:

View / Change / Remove drive letters assignment in your system

View / Change / Remove drive letters assignment in your system

www.nirsoft.net

Click to expand...

It shows the drive letter when the drive is allocated and accessible but not when the drive is in this partially allocated state. I'm guessing that the drive is really fully unmounted and deallocated, but Windows still has the drive letter reserved.

Update: A clue:
Registry entries while drive is accessible:


Registry entries after sleep - drive not accessible:

No longer a drive letter, but GUID (or whatever that is) still exists.
And the record data is "VeraCryptVolumeM".