WayneHXL

I've been using CCleaner before and after upgrading my Windows 7 to Windows 10. There seems to be no problem with it and it's been cleaning my computer fine. Try to reinstall a fresh new CCleaner after upgrading or after downgrading your Operating System.

Are you using the default cleaning options? What did you do before the problem occurs (cleaning, changing settings, wiping free space etc)? Method to recover: In Windows 7, you can try to use the System Restore to restore/recover your computer back to the last restore point which was created before the problem happens. However, this doesn't always work, but it's the best shot you'll have. Anyway, this certainly sounds like the work of a virus. Try to scan for virus with your antivirus if possible.

[sOLVED] Hello. I've recently encountered this crash problem in CCleaner when it performs cleaning. I've attached a picture below to clarify what I'm talking about. It has come to my attention that when I uncheck the Internet History of Firefox under Application tab, the problem seems to disappear. *This never happens before on the same version of Firefox and CCleaner, it just happens out of the blue. SOLUTION: It turns out I had a broken Admin User account on my computer, so creating a new one solves this.