Backups fail: "Failed to get the size of '\\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy??' - The system cannot find the file specified" (4041240)

Backups of one or more volumes fail with an error: "Failed to get the size of '\\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy??' - The system cannot find the file specified"

This issue may be accompanied by volsnap Event ID 36 in the System event log: 

If you are seeing the backup failures in Rapid Recovery and the volsnap errors in the event log, can lift the size restriction on snapshot growth.

First, check to see whether the VSS snaps are set to default:

VSSADMIN LIST SHADOWSTORAGE - If nothing is returned then defaults are configured.

If you are running in the default configuration, run the following command for each volume:

VSSADMIN ADD SHADOWSTORAGE /FOR=: /ON=: /MAXSIZE=UNBOUNDED

You can run this command on the partitions without drive letters, such as the System Reserved Partition, by temporarily assigning a drive letter to the partition, then removing it after running the command.

If you already have a shadowstorage configuration, you may use the VSSADMIN RESIZE SHADOWSTORAGE command to set the existing shadowstorage size to unbounded

1. On the Agent system and open My Computer
2. Right-click on the drive that is failing and choose “Configure Shadow Copies”
3. Highlight the failing drive and click the “Settings” button
4. Choose the “No limit” radio button
5. Click OK to save the setting.
6. Click OK again to close the Shadow Copies dialogue box