Nergal, thank you for your reply. Yes OS X 10.13 came out on Mon. the 25th but what does that matter? It’s not like no one knew about it. This is not the first time OS X has upgraded and CCleaner has lagged behind and would not work with it for sometime. I do have Pro but it is over a year old but since I did pay for it, I expect it to work. Everything else on my computer is working with the new system. Everything that needed upgrading did it before the release date of Sept. 25th. Why is Piriform not on top of things, again?