Suddenly starting today Ccleaner can't fully clean Ccleaner Browser it says it is open and then it can't close it. I haven't done anything different. Even rebooting dosn't help.
Sometimes a process in a browser, or other app, can get stuck open and can't be closed normally for some reason.
Try opening Task Manager, click on CCleaner Browser in there and 'End Task' on it to force it to close.
Do it for all instances of CCleaner browser that may be showing there.
Or restarting (not shutdown/reboot) your machine should do the same job.