Answer to: Hard drive is not showing up on my computerOkay, so I had to fight this today, and I figured out a way to at least fix the hard drive. First of all, update to Sierra if you are on Mac OS. El Capitan was a pain in the a$$. Next, open the WD Disk Utility app, NOT the mac one. Select "Erase" and then check the box on the right, NOT the left. The left will not erase first for some reason. Erase the right first, then the left. Boom. Your hard drive is ready for war again. HOWEVER if you need to get those files off of the hard drive, do not mess around and go to a computer repair shop. If you can, back up your important files temporarily to iCloud or some other service. Disk Warrior is supposed to work great but I didn't exactly have $100 lying around. After this is said and done, I still recommend buying another hard drive just in case.