I have found that when using disk cleanup in Vista it some back with an enormous amount of error messages that it can get rid of. This being Vista this is not a surprise. What is a surprise is that the size of the error messages can exceed the size of the disk itself. By a factor of more than 4. And if you try and actually RUN disk cleanup, you might as well have told it to erase your entire disk. What the heck is going on here? This behaviour is repeatable (on my machine at least)

beep, Sound like you are suffering from a known problem with a solution mentioned here:
http://www.winhelponline.com/b.....istration/

Thanks for the suggestions. I do use CCleaner now because I must regard MS disk cleanup as malware. I also happen to like hibernation (when you can get it to work in Vista) and disk cleanup tends to dimantle it. Also thanks for the winhelponline blog. At least it's not just my machine.

beep, if you notice in the discussion at the end of that blog post, there is some suspicion that registry cleaners can actually cause the original problem. However, ccleaner is not among those mentioned.

Also, Disk Cleanup chooses to delete the hibernation file (hiberfil.sys) and disable hibernation by default. To prevent this, just remove the check mark from "Hibernation File Cleaner" before letting it run. To get your hibernation back, use this command line:

> powercfg -hibernate on