- Make sure the installer isn't named CCleaner.exe, if it is rename it to something else like: ccsetup220.exe
- Exit running programs that may interfere.
- Reboot your computer.
- If all else fails do a clean install of CCleaner by uninstalling the previous version, followed by a reboot.
Also only download CCleaner from the CCleaner homepage, or from FileHippo.com here.