CCleaner v5.44.6575 is unstable for me, too.
--First, it wouldn't install, instead showing a message box that stated "CCleaner has stopped working."
--Then, when I tried again, it did install, but would not run and again showed the same box message.
--Then, I was able to change the Cleaner Results option to a file list (from summary) and did get one clean run.
--Last, I tried to run it again, got the message box, and the program closed.
--I went back to v5.43 which works if I change the Cleaner Results to file list.
Details: ccleaner v5.44.6575 - Windows 8.1 - Kaspersky Total Security 18.0.0.405