I've bought an External HDD to connect to my MacBook Pro via USB. I had a few problems getting it working, but I deduced that these were down to a slightly loose cable and decided to put up with it. However, the drive is now locking me out of OSX - I can't click on anything - when I try to use it. I've just plugged it in to my girlfriend's MacBook, and it's working perfectly: mounts immediately, I can move the drive around physically without it disconnecting. So I now think the problem lies either with my MacBook Pro or with my install of OS X. I'm pretty new to Macs having just switched, so would really appreciate any help anyone offer to get this sorted out. Many thanks in advance.