The latest version of Avast is mucking up all manner of settings within windows and other programs, CCleaner included (can no longer use it to edit start-up items or scheduled tasks for example). You will probably find you cannot change or create new power plans as well, another problem I've found on all the PC's I've installed Avast on (so it's a programming issue with Avast, not our hardware).

This still has not been fixed (after a few weeks now) so I can only suggest finding the previous unbugged version and going back to that (ignore any program update prompts) until Avast sort this mess out.

Yes. Today I upgraded the software and then used CCleaner. Hell! My Avast was working before running CCleaner. Even after Avast upgrading. I think CCleaner removed any important file which is necessary to start Avast each time.
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