Free space wiping stops

Hello, I like Ccleaner and I have been using it to wipe my harddrives free space. However I have noticed that after it has finished wiping the mft space, it will start wiping the harddrive and it says something like 6 hours left and from there on it goes wiping the free space for the first 40-50 or so Gigabyte (of 250 Gigabyte of my HDD) for 1-2 hours and then it's just over, finished, when one minute before it was only at 35% and said that 4 hours were still left.

So I wonder is this a bug? Or does Ccleaner only wipe the harddrive space that actually had contained files at one time already?

Thanks

Martin

. . . is this a bug?

Not a bug cos most guesstimates are capricious. Ages ago I learned to ignore them. Drive Wiper/free space wipe works fine on my pcs. :)

After wiping you can check the effectiveness by using Recuva, and ☑ticking these boxes . . actions3.jpg . . overwritten with 000000000000.