This is not quite the same problem that tigerbill88 has been experiencing, but it may be related.
I am using also using Windows 10 64 bit
I have been using CCleaner (Free), successfully, on all my PCs for hundreds of years (well, at least 20 anyway!)
I have never had any issues until the last 2 (failed) attempts to install the last 2 updates.
No error message - the install process just stops after I click the Install button on the (usually) final install dialogue box.
I ignored it the first time and continued to use the outdated version, as I didn't have the time to devote to anything too time consuming.
This time I tried everything, including a clean install, and everything on the list posted by Andavari, July 5, 2006 in CCleaner Bug Reporting
Lately, I don't use any AntiVirus products other than the built in Windows 10 "Windows Defender".
After uninstalling the last version I had, I have finally managed to install v5.60.7307 (64 bit) - after downloading the zipped 'Portable' version from the official site.
However, I'm not quite sure what a "portable" version really is !
I have had to re-populate my list of "Cookies to keep", and of course, the app no longer appears in my Windows list of applications (does this really matter?}.
I have ticked the box in Options to "minimise the app to the system tray", and created a shortcut on my desktop to start the app that way when I shut down my machine.
I assume this will mean the app will function pretty much the way it always did in the past.
I am baffled as to why this has started happening and the apparent lack of posts by any other people experiencing the same issue - so I'd be grateful for any comments/guidance.
Can anyone tell me whether this version will continue to inform me when a new update is available? and can anyone reassure me that I will not have to repeat this whole process every time I try to do updates in the future?
Many thanks in anticipation.