DPM backup system state windows 2008 failed

Ah, it has been much too long and I have so many things I want to blog about and things to make you aware about. They are all marked, but due to having been sick two times in two weeks I have not gotten round to blogging yet. But….
This weekend I have upgraded a windows 2008 machine to windows 2008 R2. It was a domain controller. I am using DPM 2010 beta to backup my environment.
I noticed that since the upgrade the dpm backup of the system state failed. It could not create a replica and it could not do a consistency check either.
So onwards to the aplication event log on the domain controller:
The backup operation attempted at ‘ý2009ý-ý11ý-ý14T19:00:33.965515400Z’ has failed to start, error code ‘2155348032’ (The backup storage location is invalid. You cannot use a volume that is included in the backup as a storage location. ). Please review the event details for a solution, and then rerun the backup operation once the issue is resolved.
SO, it is complinaing that I am making a backup to the same volume. This machine only has one disk and always worked before the upgrade.
Well, the solution was to add a registry entry to make it not complain about system state backups to the same volume. This is from kb article 944530:
To enable the system state backup files to be targeted to critical volumes, you must set the value of the AllowSSBToAnyVolume registry entry under the following registry subkey:
Create a key called “SystemStateBackup”
Set the value of this entry as follows:
Name: AllowSSBToAnyVolume
Data type: DWORD
Value data: 1
In my case the SystemStateBackup key was not even there. But after creating this a simple Check Consistency in DPM caused it to sync the whole lot.
Bob Cornelissen