CCleaner wont cancel

I wanted to cancel CCleaner while it was scanning my pc. But when I pressed cancel it just had a loading sign next to me cursor. Since it was loading for way too long I decided to try opening task manager and end the task since it was unresponsive, but task manager wouldn't load. Not only that, but I couldn't properly shut down my pc! I press shutdown, Nothing happens. I soon learn that I wont be able to close any programs or run any new process until CCleaner cancels. I was forced to cut the power to my pc. This is a serious bug and should be addressed immediately.

Can you please give a bit more info.

Which operating system? 32 or 64bit?

Which build number of Ccleaner?

Was this just after installing Ccleaner or have you had it on for a while?

If it's a new install of Ccleaner, where did you download it from?

Is all your anti-virus/security software up to date and scans clean?

Do you have wipe free space checked off

Not good if secure deletion/wipe free space/drive wiper are enabled and this happens as that can make your system unbootable and Windows reporting the disk is in the RAW format - I know from prior experience using a different tool to wipe free space.