Strange appearence of a new Drive designation

Dear Opus

This may have already been answered, but I can't quite understand the answers.

When I open OPUS I suddenly appear to have another drive 'M'. If I simply use explorer no M: drive appears.

Can anybody explain what is happening and how do I get rid of this phantom drive.

I'm trying to attach a picture of the two looks, but can't quite work out how to do it.

Cheers, Stephen

What’s in the drive? That may be a clue about where it’s coming from.

Just drag and drop the screenshot in the editing part of your answer if it's a file, or copy/paste in the same region.


If I click on the M drive it is empty,

  1. What happens if you type M:\ into File Explorer's path field and push return? Does it show the (empty) drive then, or an error message?

  2. If you open Disk Management (type "partition" into the start menu and it's usually the first match), does it show anything about that drive there?

  3. Make sure Opus isn't running Elevated or "run as" as a different user account to normal. (See Why NOT to run Opus as Administrator under UAC for more detail.) That can result in different drive letters to software run normally.

This looks like this M:\ drive is a "copy" of C:\ drive (as the one you can get with the dos SUBST command which can create virtual drives that are some kind of shortcuts to another drive (possibly with subpath).
The strange part is that it's not visible from explorer and seems empty when you go into into it (whereas ThisPC view shows a drive with approx. 240Gb of data).
Could it be related to Acronis Backup ?? (see https://forum.acronis.com/forum/acronis-true-image-2019-forum/acronis-drive-letter-error?ckattempt=1 or https://forum.acronis.com/forum/acronis-true-image-home-forum-older-versions/wrong-drive-letter). It looks like they tend to use that drive SUBST ...

Thank you everybody who has responded. It is to do with my backup software Acronis. I've managed to just about understand it!!!