CCleaner keeps being uninstalled

CCleaner, but not Speccy and the others, routinely vanishes from my PC, running Windows 10, 64 bit. Several other programs are also being uninstalled without my say-so. My work-around is to download the free version of CCleaner and use it until it disappears again, but if anyone has a bright idea I'd love to hear it.

Could be the installed antivirus doing it.

Which version/build of Win 10 are you running?

And which antivirus (and version if it's not Windows Defender)?

Are you doing anything in particular when CCleaner/other apps get uninstalled?

What other apps are being uninstalled?

Windows itself will sometimes uninstall incompatible apps, and will remove older CCleaner versions, but it shouldn't have a problem with the latest CCleaner.

(Unless maybe if you are on an insider build).

Your anti-virus may also be uninstalling, or quarantining, things that it wrongly sees as threats.

(Or there is a slight possibility that you have a malware infection that your AV hasn't picked up).