SQL differential backup terminates abnormally leaving partial files unnecessarily consuming space.
SQL differential backup terminates abnormally leaving partial backup files.
There are two approaches to correcting this issue. Either, the underlying VSS errors can be addressed or the Unitrends agent can be configured to use VDI to perform the backup rather than relying on the VSS writers.
Performing SQL backups using VDI instead of VSS
Unitrends VSS SQL agent errors and warning messages
This condition typically occurs when a SQL differential backup terminates abnormally. The backup may not complete due to space constraints on the SQL server where the VSS snapshot is being stored, a network disconnection or another VSS error which can be found in the Event Viewer of the SQL server.