I bought an extra hard drive for my xbox and I kinda guessed it would be trouble from the start. The seller tried to label it as 20 GB, and after configuring it and clearing up about 3 GB of invisible space (I say that because there apparently was nothing on it. I'm assuming now the person never cleared the system cache after deleting everything) to its original 16 GB, I got a few error messages that read to the effect that it hadn't been set up properly from the start. I also bought a used transfer cable along with it, but as far as I can tell they're both legitimate Microsoft hardware.
So I moved a few things over to the new hard drive with no fuss besides one message saying I'd might have to redownload the licenses for the data. However, I tried testing out moving my profile between the two drives and had some problems logging in (may have been tied to my iffy modem connection) so I disconnected the new drive from the transfer cable. About a week later I decided to try to switch the drives again. I honestly cannot remember if I did manage to turn off the xbox first before yanking out a the drive, though I remember attempting to a second before I pulled it out. When I tried to access the drive through the memory screen, it couldn't be read. I tried both drives and nothing. Then I tried accessing them both from the transfer cables and found they both work. My question is twofold: is there any hope of fixing this without turning my 360 in for repairs, and how much will a repair run me. Last time I sent it in to fix the Red Ring of Death it cost me almost 300. Though it;ll be annoying no doubt, I don't think it'd be worth that much to get my game data back. The only real problem is the new DLC i just bought and downloaded to that drive, but buying more points and a new transfer cable is honestly looking like a preferable option.
Sidenote: There's also been a problem with the disc tray opening at times. I also think I may have yanked out the hard drive without turning off the xbox before this, but this is the first time this problem occured.