By your description, I'm kinda confused as to what you are trying to accomplish.
A. CCleaner "Cleaner" Module ? You want to get rid of junk files to free up space on your HD ?
You can recover free space by getting rid of junk files. Using this option it may show you that you have 344 GB of junk that can be safely removed based upon the checkboxes you want to clean in the left column
B. CCleaner "Drive Wiper" Module ? I', assumong that thos is the goal here and you want to remove the "ghosts" of all old files that have since been deleted, but which are recoverable unless they have been written over. ? Reasons you might want to do this would include, a) you want to destroy the drive or give it or the machine away, b) the police were just at your house and advised that they are coming back with a search warrant, c) don't want your now tech savvy GF / wife discovering your recently deleted porn video's or d) your name is Michael Cohen.
All kidding aside, if you don't "wipe the free space", it will just get written over. You will not gain anything other than a measure of privacy should someone with tech skills gain access to the drive. So if it was cleaning 344 GB of space that now contains ghosts of deleted files, you have made half of about those files unrecoverable using special tools. The space is not "returned", it was always there for you to use.
- Let's say a 2 TB drive had 344 GB contained "ghosts of old files" that could possibloy be recoverd using special tools and 166 GB of virgin space. Your drive status is:
1,500 GB of files
344 GB of "ghost" images of your files that could potentially be recovered (Free Space)
166 GB of virgin space (Free Space)
All totaled, you have 500 GB of free space
After "wiping" 160 GB...m your drive status is
1,500 GB of files
184 GB of "ghost" images of your files that could potentially be recovered (Free Space)
160 GB of random 1s and 0s that can not be recovered (Free Space)
166 GB of virgin space (Free Space)
All totaled, you have 500 GB of free space ... only change is 160 GB of your 344 GB of files can not be recovered and read.
https://www.ccleaner.com/docs/ccleaner/using-ccleaner/wiping-free-disk-space