My apologies if this has been covered before, keywording something like this is difficult....
I have an old Athlon 1.24ghz, 1.5gb ram, 500(well, 475) gb drive with 430gb free (nicely de-frag compacted and ready), WinXP SP3 and all drivers max-updated, it's running smoothly. I'm handing this computer off to someone, so I wanted to wipe it of all but a few folders of pics and stuff I'm also handing down. After a few days and many restarts doing physical clean-out of sensitive files and uninstalling several programs and a couple old/defunct sound/graphics cards, I was ready for CCleaner. So I dl'd it and did the Registry and the cleanup, which seemed to work fine and found a lot of old junk in the registry and hidden elsewhere.
Then when I went to drive wipe and specified free space (and MFT) and ran it (3-pass). It started out fine, it was kind of cool to watch the timer crawl up first to 11 hours and then back down as it went along. About 3 hours later it said it only had 5 hrs 37 minutes left, and had done somewhere between 150gb and 200gb.... But I happened to be sitting there doing other things in front of the screen and saw it ZIP right to 100% finished, from there.
So.... is that common/normal operation for CCleaner? No errors or anything came up, I guess I expected it to crawl ALL the way to 100% slowly and possibly still be running next morning when I got up. How can I be sure it actually cleaned the whole 430 gb, if it SEEMED to just skip to the end? Sometimes progress bars for other things, like program (un)installs or online downloads, do this too... I'll run it again tonight just to be sure, and watch again, but.... is this normal? Some setting I should change, or other program I can DL to cross-check and make sure?
It sounds like the last part of the drive did not have anything to delete.
Remember When you regular delete something the bits are still there. This is the information that WFS is wiping. So those first slow hours were due to there actually being something there and after that it was just a matter of quick wiping.
(This is an educated guess by I'd wager it is correct)
Hmmm..... You could be right, but I'd be surprised due to past usage of the drive. I used to do a lot of home video and VHS capture/edit etc, many years ago, and at one time or another the drive was pushin' FULL. Maybe CCleaner came to a HUGE area where there never was anything but 4.3gb DVD-ready MPGs one after another, it's possible. But I guess I'd figured it would keep 3-pass blanking over those 'leftover bits' areas just like any other area, taking no more or less time than any other to be wiped.
Is it also possible that, somehow, the actual wipe process just 'outran' the progress bar display, so when the former was finished the latter had nothing left to do but say "Done"? Either way, to go from 5 1/2 hrs left to Zero in just a second or two was disconcerting. I'll run it again tonight.
Can't forget also with secure deletion the time is an estimate. I don't know how the internals of CCleaner determine if an already irrecoverable file needs to be wiped or not so perhaps (this is just a guess) some of what you had was already irrecoverable and thus a waste of time to attempt to wipe. Of course you may be able to verify this by using Recuva.
That was my first thought. But then wfs writes a file, or files, large enough to fill the volume, as I understand it. As far as I know there's no selective mechanism not to overwrite some clusters. If there were it wouldn't be a drive wipe. I'll go for it being a builder's estimate.