Challenge
Backup job fails with the following error:
Error Cannot find shadow copy of volume VM (X:) (System.Exception)
Cause
The disk ID in Windows has changed since the last backup run and does not match the ID stored in Veeam database. This can happen if the EFI system partition drive has been backed up in the volume mode.
Solution
Reset the database information so that it recognizes the new disk ID from Windows.
To do so without clearing up the database, set the backup job to run a file level backup, adding files that are on an active volume. Run the backup job immediately afterwards. If the job runs successfully, this should mean that the disk ID information has been re-added to the database. It should be safe to change the backup configuration to a volume level backup.
More Information
Another option would be to recreate the local database. For more information on how this can be done, please see the following KB (steps 1 - 4)