DPM cannot create a backup because Windows Server Backup (WSB) on the protected computer encountered an error (WSB Event ID: 521, WSB Error Code: 0x807800A1).

Error:
The following alert became inactive at 27-9-2011 3:15:52.

Status: Inactive

Data source type:

Data source: System Protection

Description: Last 1 recovery points not created.

DPM cannot create a backup because windows server Backup (WSB) on the protected computer encountered an error (WSB Event ID: 521, WSB Error Code: 0x807800A1).

For more information, open DPM administrator Console and review the alert details in the Monitoring task area.

Solution:

Some noncritical volumes are included in the system state backup image when you use the "-allCritical" switch in Windows Server 2008 R2 or in Windows 7 only for non SP1 systems. SP1 includes this hotfix.