Recuva doesn't show found files

Since a few weeks I am a user of Recuva. My first attempt was successful but now, on another computer, I have this problem. As I am sure there are deleted files, Recuva doesn't show any when it's done. When I stop the process during fase 1 there are many files found, but when I let the process (deep scan) come to an end there are none.

Am I doing something wrong?