Change the location of the system state backup file

As you might know, DPM stores the system state of a machine first locally on the protected machine before copying the data to the DPM server. DPM select the most suitable disk for the local copy of the system state when you run the backup for the first time. You might want to change this location when available disk space changes or when you add additional disk to your system.
This can be done by editing the configuration file on the protected computer. 

(Technet)
The backup file of system state is created at %systemdrive%\DPM_SYSTEM_STATE.

To change the location of the system state backup file

1.On the protected computer, open PSDatasourceConfig.xml in an XML or text editor. PSDatasourceConfig.xml is typically located at install path\Program Files\Microsoft Data Protection Manager\DPM\Datasources.

2.Change the <FilesToProtect> value from %systemdrive% to the desired location.

3.Save the file.

4.On the DPM server, if there is a protection group protecting the system state of the protected computer in step 1, run a consistency check.

5.The consistency check will fail and generate an alert. Perform the recommended actions in the alert as follows:

a.In the alert details, click the Modify protection group link, and then step through the wizard.

b.Perform a consistency check

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When you have issues with backing up the system state of the machine you should always check the logs on the local machine.

-Application log
-C:\Windows\Logs\WindowsServerBackup

FI: Backup started at ‘’ failed with following error code '2155348165' ( There was a failure in preparing the backup image of one of the volumes in the backup set. ). Please rerun backup once issue is resolved.