SQL backups or restores fail with VSS errors
Enable SQL VSS writer
You must ensure that the SQL VSS writer is in a stable state to back up SQL databases. The SQL VSS service is used for taking a shadow copy of your databases, which will allow Unitrends to back them up.
If the Unitrends agent does not have access to the SQL VSS writer, a backup cannot be performed.
On your SQL server, open Services. Find the service called Microsoft SQL VSS Writer and start it. Ensure the service is set to Automatic.