If I understand you correctly, you are running Drive Wiper? If so, and if you have run it against your system drive, then it will wipe the free space. To do this it will fill the drive with dummy files and then delete them, so for a short period of time your disk will be full, but at completion you will not have lost any free space.
With all due respect Soulmte, you shouldn't ever be running something of which you have no understanding.
There's nothing wrong at all with being unaware of what something is or does on your computer, but to bash ahead and ask questions afterwards is a sure road to disaster.
I think I've said this before on here, but far better to ask "what does this do" rather than "how do I fix this"?
There are guides here for all Piriform software, but I've linked you to the one relevant to the "Wipe Free Space", which will give you a full understanding of what the feature is and does ...