Disk Optimization Error: Drive C: Error - not completed

My Norton 360 flags my Tuneup as needing attention.  When I impliment the fix, Tuneup starts the Disk Optimization.  After a few minutes it stops with an error.  Clicking View Details opens the Details window that reads Drive C: Error - not completed. as the issue.  I've googled and searched the forums and can't find a solution.

 

Specs

Norton 360 v20.4.0.40

OS: Windows 7 Home Premium SP1, 64bit

 

Thanks for the help.

 

Cheers,

Kawzman