Cleaner seems to be running in an infinite loop

When running Analyze, program gets to 23% quickly and then just continually runs but doesn't progress. It happens at System temporary files. So I just reran the program unchecking that. Any advice for how to clean what I skipped? How important it is to clean these files?

Thanks.

how old is the PC and when was the last time any system maintenance or file cleansing was done?

or in other words, you may simply have so many temporary files built up that it is taking ages to Analyse.

as CC does its analysis, your AV software would be checking the files accessed, maybe you have other background tasks slowing it all down too.

try running the next CC with the PC in Safe Mode, that way there will only be the core essential background tasks running as CC does its thing.