I actually have Testdisk from recovering another corrupted drive but it wasn't able to recover everything, only a small percentage of the files, and many were incomplete and had no file information.Its a scary thought that initializing it will wipe everything but it doesn't. More than likely once it is initialized it will show as a raw partition. There is a tool called Testdisk that can recover the partition table like nothing happened and I have had good luck with it but YMMV.
Oh yes, I think I used photorec in the other case.I think you are confusing file recovery with partition recovery. This very symptom is a result of the partition table being lost and I performed this very action three months ago on a USB hard drive. Like I said, it found the partition and rebuilt it in the blink of an eye with even the name of the partition. File recovery when the partition table is lost is always dicey no matter the recovery software because you may end up with a single folder full of randomly named documents and images.