Ossan

Hi, I used the free version of Recuva. I was happy when the program detected over 1800 pdf-files at an formatted USB-Stick. But when I tried to open the recovered files they were all empty or Acrobate-Reader couldn`t open it. So my question is: Is there a better chance to make the recovered files useable, when I buy the pro version? Is there any difference? Thank you for your help!