Does stopping drive wiper (free space) mid-way negate all he wiping?

[kelvin32134]

If I run the drive wiper, free space, 1 overwrite....and then close ccleaner when it's at 50%

Did it still wipe 50% of the free space? or does it undo all the wiping ?

[nukecad]

A drive wipe (free space or entire drive) works by writing random files, (usually containing one and zeros, or X's and Y's, etc.), to the drive to overwrite whatever was there, so that anyone later trying to recover what was originally there only gets that random data.

You can safely cancel a drive wipe. it won't stop straight away because it has to clean up and remove the random files it had already written up to when you clicked cancel.
It can't undo what it has already overwritten that's gone, but it won't overwrite any more.

However if you abort a drive wipe by force closing the app (or if it crashes) before it has finished and had time to clean up those random files then you will have hundreds (thousands) of files with random odd looking names left behind and taking up space on your drive.

If that does happen, and we occasionally get posts where it has happened eg. when the machine has been powered off unexpectedly in the middle of a wipe, then you have to clean up all those random named files manually yourself.

Running a free space wipe again won't do it for you, for all a new free space wipe can tell those are valid files and not free space.
(Of course an entire drive wipe would remove them along with everything else on the drive, leaving it totally blank).

So yes, you can stop a wipe part way through, but you should only do it by cancelling and then letting it finish cleaning up what work it has already done.

PS. 1 pass is all you need when wiping a HDD, the multiple pass options are just a holdover from years ago when it may have been beneficial to do more than one pass. Nowadays doing more than one is just wasting time.
PPS. SSDs don't normally need wiping, their built in garbage collection and wear leveling mean that they can't usually be recovered from anyway.

[kelvin32134]

So I did press "x," rather than cancel, at about 60% through. Does that mean about 60% of the free space is now occupied by these random files?

Just for understanding, the only difference between hitting "x" and "cancel" is that cancel deletes these new random files?

Edited April 11 by kelvin32134

[nukecad]

I'm not sure if hitting X would cancel the wipe properly or just abort it, but I would check to see if you now have far less free space than you had before.

If you do have less than before then it's time to go looking for and manually deleting those files.

Whilst I said above 'hundreds' of files that was a general statement for drive wipers.
CCleaner's wiper tends to use less, much larger, files and they may be in a folder (Which makes them easier to find).
Here are a couple of older threads about it: