Full System Backup will not complete, reporting a problem with BITS VSS writer(Background Intelligent Transfer Service Volume Shadowcopy Service writer):
Error: Selected writer 'BITS Writer' (48b0be47-4969-d978-e0c1-7af028f300b1) is offline
Error: Backup failed: A selected writer was not found
The BITS writer may go offline when Windows updates have a pending reboot.
This offline status then prevents Full System Backup from running.
It is possible that restarting the Background Intelligent Transfer Service and the Redstor client service can resolve this issue temporarily, but this is not always successful.
The recommended solution is to reboot, allowing the updates to be installed. Please note because of the way Windows updates can be queued if there is a large backlog of updates more than one reboot may be required.
In the event that a reboot does not clear the error and the BITS VSS writer cannot return to a usable state, you may need to investigate further.