I recently came across a problem with System Center Data Protection Manager 2012 (DPM) whereby backups were failing with the error “An unexpected error occurred while the job was running. (ID 104 Details: The device is not connected (0x8007048F))”

Unfortunately, I wasn’t able to resolve the problem without data loss, but these are the steps I followed to get DPM working again.

Firstly, go to Disk Management by opening Server Manager, then expand Storage.

I saw a large number of RAW volumes with 100% free space.  I had to delete each of these volumes, by right-clicking and choosing delete.

Once you’ve deleted all the RAW volumes, open the DPM Management Shell and run DPMSync – ReAllocateReplica.  This recreates the volumes for each item that’s protected by DPM where the volume is missing.

Open the DPM Management Console and start an consistency check of all data sources.  This ensures DPM has an up to date copy of all protected items and can resume backups.