Since moving from Windows XP to Windows 7 in March, I've been having very little luck with Recuva. Files I try to recover are shown as overwritten nine out of ten times, seemingly regardless of the size, age or original location of the file I'm trying to recover.
Tonight I was trying to recover a 50MB file I had just deleted from a 16gb thumb drive. Minutes after deleting the file (and without any further use of the drive) I wanted to get it back. Using Deep Scan for all deleted files, 33 files were found. The one I wanted, and 31 of the others, were all marked as unrecoverable because they were overwritten. Ironically, the only deleted file marked recoverable (in excellent condition) was a two-year-old file that is by far the largest of the 33, at 770MB. 28 of the files -- including the one I wanted to get back -- were marked as overwritten by one specific 867MB file (an mp4 video, call it ABC.mp4) that is about 6 years old, and that I haven't accessed in at least a year.
As a test I then tried deleting two more files I no longer need (a 53MB mp4 and 321MB mp4) and then ran Recuva. Sure enough they were both shown as unrecoverable because they were overwritten by ABC.mp4.
This is FAT32 drive, but subsequent experimentation with an NTFS thumb showed a similar pattern.
Any thought on what might be going on? I also tried a different recovery program which similarly showed the just-deleted files as overwitten (although that program doesn't identify the overwriting file), so it may not be a Recuva-specific issue.
EDIT: To experiment a little further, I created a 4kb text file, saved it, and immediately deleted it. It is shown as recoverable. But now that one previously recoverable file (the 770MB one) is also shown as unrecoverable because it was overwritten. But NOT by ABC.mp4. Instead the overwriting file is that 4kb text file I had just created and deleted (and there was 1.36GB of free space when I did so).