I think you've misunderstood, I can't start Drive Wiper. In fact I can't even select the drive to start it, when I move the mouse over the C drive to select it and wipe the free space I just get a blue circle. I can never select the C drive to wipe the free space.
Does this function actually work? I've tried on multiple laptops (HDD) to wipe the free space, every time all I get each time is a blue wheel when I try and select the drive.