I’ve had this same issue on my dad’s computer.
Eventually found out there was a virus active on his pc that created two lines in the registers that prohibited CCleaner to work properly.
Before deleting those line CCleaner stuck on 2% scanning and eventually crashed.
After deleting those lines it worked like a charm 👌🏻
Fixed it by installing Malwarebytes. Rebooted Win10Pro into save mode. Scanned the C drive. When you delete the quarentined files it tells you to reboot. It will do a normal boot back to windows.
After booted in windows run Malwarebytes again, and found a few more files and the two register lines poped up.
When those are deleted it worked fine again 👌🏻