Your environment is running DPM Server and attached with tape library. It’s has been running fine and suddenly tape library/drives fault. Principal came and replaced either tape library or drive. New hardware definitely will has new serial number and probably resides on new SCSI BUS, LUN or Ports. Therefore you need to do remap of tape library.
To verify , open DPMLA.xml from Program Files\DPM\DPM\Config\
Compare from the one listed in DPM Console.
You will notice serial number and drive bay index is different.
1. Make sure DPMRA services is not running
2. No cleaning tape
3. Remove any tape from drive.
1. Manual modify the DPMLA.xml
- Serial number
or execute DPMDriveMappingTool.exe from ProgramFiles\DPM\DPM\bin
Lastly open DPM console and click Rescan