An organization uses System Center 2012 R2 Data Protection Manager (DPM).
Backups of virtual machines that are hosted on local volumes complete successfully. Backups of
virtual machines that are hosted on storage area network (SAN) volumes fail. You receive the
following error message in the Windows Event Log:
Backup failed with the following error
An error occurred:
Writer ‘Microsoft Hyper-V VSS Writer’ reported an error: ‘VSS_WS_FAILED_AT_FREEZE’. Check the
application component to verify it is in a valid state for the operation.
You need to ensure that all backups can complete successfully.
What should you do?

A.
On the Cluster Shared Volume (CSV), grant administrator rights to the DPM server computer
account.

B.
On all Windows servers in the environment, enable the Volume Shadow Copy Service (VSS).

C.
Install and configure the Volume Shadow Copy Service (VSS) hardware provider from the SAN
vendor.

D.
On virtual machine files hosted on the Cluster Shared Volume (CSV), grant administrator rights to
the DPM server computer account.