Delete old shadow copies from Windows Server Backup drive to free up disk space

A single physical server (2016) running the basic Windows Server Backup to a locally connected USB drive ran low on space on the backup destination. There was only a single full backup image (and associated files) so not a lot to do any manual pruning on. Although WSB claims to manage the space to cycle through and delete older copies, this doesn’t always seem to work as advertised. On this occasion, removing some of the old shadow copies on the backup drive was the answer.

Note: You may need to assign a drive letter to your backup drive (in Disk Management) before proceeding.

To list the shadow copies currently stored on the backup drive, open an administrative command prompt and run:

vssadmin list shadows /for=f:

[Where F: is the drive letter assigned to the backup destination]

If there are a number of shadow copies, and you are comfortable deleting some – or all – of them, you can do so with another command:

Type diskshadow and hit Enter
To delete the oldest stored shadow copy: delete shadows oldest f:
To delete all stored shadow copies: delete shadows all
To delete a specific shadow copy: delete shadows id <shadowID>

<shadowID> can be identified from the earlier vssadmin list shadows command