CCcleaner tends to eat things it shouldn't.
So do several others that I've tried over he years.

Glary has proven to be safe; never cause a side issue.
Glary Utilities... http://www.glarysoft.com/

For Anti-virus, Vipre has proven itself. It's not free, but it's not
at all expensive either. And it does work, which is more that I can
say for the free ones (or the expensive commercial stuff either!).