Drive Based Back Up Fails to Complete

I'm running Ghost 15.  I have a drive based backup job scheduled to run on Thursdays and Sundays, and a file backup every day.  The drive based backup is scheduled to run a couple of hours before the file backup.  They run in the middle of the night.  On several occasions the drive based backup has started, but gets hung up at 5% progress.  The file backup never starts presumably becuase the drive backup never completed.

 

The only way to stop the hung drive based backup is to re-boot the computer.  Ghost then asks if I want to re-attempt the drive based backup.  If I do, it seems to work fine.

 

What is up?