My 360 died on me recently. I sent it in to be repaired. I got a replacement console. My 500 gig official HDD AND my WD external 1tb hdd stopped working properly. I'll elaborate.
Both were working fine with my previous console. They were working ok with the replacement for about a week. I actually thought I had been sent a faulty system, so I returned it, however, the replacement for the replacement had the same problem.
The 500 gig will install games and saves, BUT, it will not play disc games. I will start the game, and the screen will go black. sometimes the game will start in about 3 minutes, and then freeze, or the screen will just stay black. When I try to move files from the 500 gig to the external, the files will corrupt.
I replaced the 500 gig with my old 250 gig (so glad I didn't sell that!) and it works just fine. the games will also play WITHOUT the hdd. It, apparently is the 500 gig, which I've had for less than a year. I spoke to someone from support, but he wasn't very helpful, as he didn't even know that we, as 360 owners are now able to use external drives. He suggested that I update my console by going to settings, system, Network, Wired/wireless and some kind of update prompt is supposed to pop up. The problem with that is, when I went online with my replacement console, I was forced to update--and both HDDs still failed. I'm hoping someone else here has a solution for this problem.
As for the external drive: when I plug it into my pc, I have to go to disc management and reformat. When I plug it back into my 360, it causes the external to have un allocated files.....