Checking Free Space during One Button Checkup takes forever

During scheduled One Button Checkup (w/ Norton Systemworks 2003) it gets to the Free Space step (CleanSweep Fast & Safe Cleanup) & window comes up asking "Clean Now" (it's NOT automatic so "scheduling" it is pointless because you have to be there to click it or it doesn't continue!   but anyway....) and when I do it starts to check Free Space but says "processing...wait" but goes on forever.  It's not stuck, i.e. "not responding", it just never progresses past that point so I have to just manually stop it.

 

So:

#1. what causes this?

 

and,

 

#2. is there a way to "automate" (make it) so I don't have to be there to click "Clean Now" & then close out the window?