I just got that "error opening file," but it came when I allowed CCleaner to try and update itself. To fix it, though, I didn't have to uninstall it or do anything fancy: all I had to do was to download the installer separately and then run it. However, there was one peculiarity. My natural instinct was, before running the installer directly, to go to the task manager and kill CCleaner, since, 99.99% of the time, that kind of problem would be that the installer couldn't close a file that was in use (or else that an anti-malware program was "helping" by preventing the system change.) However, CCleaner was not running. I am puzzled as to just how the original installer, run via the update within the program, could have closed CCleaner itself, yet been unable to install the new version. EDIT: After writing this post, I went to move the downloaded CCleaner installer to my archive of installers (that's to save time and hassle whenever I restore a system image via Macrium Reflect, which I do every few months: when I do so, I update all the software manually whenever possible before re-connecting to the internet) and, guess what: my old friend, access denied, came visiting. Windows would not allow me to move the CCleaner installer from downloads; it wouldn't even allow me to copy it. Worse, I took ownership of the file, and Windows still wouldn't let me. Rebooting fixed the problem: the file disappeared from downloads after I rebooted, so, in shutting down, WIndows might have killed whatever was locking the file, then finished deleting it.
ParrotSlave posted a topic in CCleaner SuggestionsIs there not some way to enable it to clean all the accounts at one time if you run it from an admin account? I have to log into each user account every time I make a new image of my system, just to cut down on the space the image will take (as well as cut down on the time to create the image.) With as much as a half gig or even much more in each account, that saves a lot of space.