I purchased and have been using CCLeaner Pro for sometime now and all of a sudden today it won't open, so I'm unable to do a scan. I have PC Matic on the computeras well but I placed CCleaner on their "white list" so that shouldn't be an issue. It just won't open!
Has your CCleaner recently (just) updated?
It can sometimes take AV's a while to recognise the new version as being legit.
So even though you have CCleaner whitelisted your AV may think that the new version is something else that is pretending to be CCleaner.