Hiya, I think I was having the same problem as the user above. Downloaded ccleaner from official website, to upgrade to 5.73 build. Old / current build 5.72, which was behaving funny as it is anyway, not wanting to leave the minimized taskbar / exit. Tried installing the new one, over the old one (having the new installer, remove the old one in the process). Installation process starts, and halts and nothing happens. See screencap below. Tried uninstalling through control panel / apps -> uninstall -> nothing happens, uninstall process just stops about 15% in and progress bar doesn't move at all. Went to url above and downloaded slimbuild. No joy either, same happened. Had to kill installer through taskmgr each time Killed ccleaner background-process through taskmgr, retried installation as administrator and it worked! Used on a windows 10, 64 bit Asus laptop. User has administrator rights.