Recuva finds deleted files and offers to recover them. If I do not want to recover but to erase the filenames unrecoverable: how do I do it? Overrite or secure delelte as suggested in the menu is not possible because "File is allready overwritten".
If you have a TRIM enabled SSD and O/S, which I guess most people have now, then a normal file deletion will erase the file clusters. The occasional defrag Optimise will clean up any clusters still hanging around. So a wipe free space is unnecessary and, as many have pointed out, can be quite wearing on the SSD.
Recuva reads the file names from the MFT. This is a protected system file and there is no legitimate way of amending it unless done by NTFS. CCleaner can do it because it asks NTFS to create new files which overwrite the old file names, which you could do yourself.
As I wondered why the option wipe c: was not activ although I had it marked at wipe free space, I changed the overwriting option from 3 times to once ... and it worked! The deleted filenames now are disappeared.