External HDD problem

Solution
You can do another thing, that is CHKDSK from CMD, see what happens. And try to plug the HDD directly to the MB, look at my earlier post.
It could be a bad connections between the drive and PC. Or the USB cable gone bad. Or the caddy/enclosure is faulty.

First make sure the connection is good. If that doesn't work then try to replace the USB cable or caddy.

Another thing you can try, place the external HDD directly to the MB by opening/breaking the caddy.