|... I had the same sort of issue in the past|
... but it was an external "usb2" drive, for some strange reason I used a different adapter (still usb2)
... the device when detected did exactly as you stated "one large" file.... awwww!
... used recovery software , I recall a "truncation error" which it "fixed".
... as I have so much fix-it software remembering which one did the trick.....nope.
... I would suggest using "ndd.exe" first which is the "dos" version of norton disk doctor (boot up with it)
... I only use "that" usb adapter in dos as it does as stated all the time to drive/files in "gui"
"...pentathol makes you sing like a canary"
... got brain freeze