Western Digital has a new 1TB internal drive that fits just fine in my 15" Unibody Macbook Pro. I needed more space so I sought to upgrade my factory 250gb hdd to this WD 1TB drive. I used disk utility to clone my previous drive. I also made sure to include the GUID partition. I booted the computer via usb connection from the new drive by holding the alt key - all this before I installed it inside my computer. It worked fine externally. I considered it safe to install it. It fit fine, and the computer booted like normal. I was excited. After about a minute of the computer being booted I get the beachball. Nothing works. I had to force shut down the computer. When I started the computer again, it booted fine but it froze after a couple minutes. I actually took out the drive and booted it externally again and it worked. But when I put it inside the computer it froze every time... and I tried several times. Anyone have any suggestions? Is it a firmware issue? Is it just a bad drive? I'm at a loss. Thanks so much for any help anyone can give.