"Wipe Free Space" not working properly

I use CCleaner v5.09.5343 (64-bit) in Windows 10 (Build 10240).

When I click under "Applications" for "Wipe Free Space", and start the cleaning process, it does not finish. At 98%, it stops and eventually cancels. I then get the message "Cleaning Cancelled (13731.799 secs). This cleaning is incomplete." I use the setting "Complex Overwrite (7 passes)."

What to do?

Thanks.

Turn off multi overwrite, it's not very useful. Also use WFS very sparingly as you gain no extra space and wear out your drive's life (especially multiple passes)