Today, I got an Error “DPM Cannot create a backup because Windows Server Backup (WSB) on the protected computer encountered an error (WSB Event ID: 517, WSB Error Code 0x5FB81E80). (ID 30229 Details: Internal error code:0x80990ED0)” on the DPM System state backup.
Also, if you take a look on the Event Viewer of the protected server, you will see Event ID: 517 that said System Writer is not found in the backup.
If you run vssadmin list writers command, you will notice if System Writer is missing from vss writer list.
How to fix the issue?
From problematic server, Open service manager and verify the Cryptographic Services is running. You may need to restart the service. After Cryptographic Services has been restarted, try to run vss admin list again and see if System Writers is back.
From the DPM server, attempt to run the System State backup that previously failed. Or, you can monitor using wbadmin get status from the protected server.