I'm so confused why this WD ATA Hard Drive is not working on my Mac Pro. Bought Brand New at Best Buy. It's a SATA Hard Drive. It look a little different then my original SATA Hard Drive that came with my Mac Pro. The only different I see is that it also have a IDE Interface, which is not required because it can either use as a SATA interface or IDE. I plug it in the Mac Pro and it not even readable when I boot up with Mac OS X Install CD. Try using Disk Ultilities to format the Hard Drive and it's not even there. This is the link the product that I originally purchased it from. http://www.bestbuy.com/site/olspage...gital&lp=8&type=product&cp=1&id=1142294266836 The only different I see is that it have an IDE Interface too. I need this Hard Drive to work bad.