Steve, I JUST went thru this yesterday with 3 thumb drives for my wife and was able to recover two of them.? I tried different ports on two different computers and was able to mount the drive once each.? Then when I tried again, it wouldn't mount.? Thankfully while it was mounted I copied all the files from the drive.? My flash drives had decade past the "format" point to "device not migrated" meaning it wasn't even assigned a drive letter.? Good luck.? Call me if needed.?
