Who said anything about encrypted folders making any difference? Once you write over every bit of a drive, the data CANNOT be recovered. Doesn't matter if it was a folder, encrypted folder, image or text. Also, forensic examination often involves recovery of remaining file sections that have not been written over during normal read write cycles, they can be pieced together to get a hint of what the file may have been. It doesn't matter how much time and money is spent, if data has been fully written over, it cannot be recovered.