If this completes successfully, click Repair Disk Permissions NOTE This may solve your problem.

Click the Verify Disk Permissions button.Do this until there are no errors or (like me) you receive a message saying that the disc couldn't be repaired. Click the Repair Disk button that will only appear after you click Verify.

Click the Verify Disk button in the Disk Utilities.Select your drive on the left navigation panel (It's probably already selected).After you've selected a language preference, Select the Disk Utility item in the list of utilities.Continue holding the keys until the Recovery Utility prompts you to select a language (Grey Screen) **NOTE:**You may have to hold the keys for up to two minutes. Hold down the Command+R keys as you start the device.Just in case you pull off the rubber coating, you'll need a case removal tool like you use to replace a cell phone screen.Recommend: A cold beer and a lot of patience.New Hard drive that is compatible with Mac.Mac running OSX Lion or later (prior versions didn't have the recovery partition).I've had little to no success with USB powered devices.

Be sure to get one with external power source.

SATA/IDE to USB Adapter (Mine was Vantec USB 2.0, but it shouldn't matter.

Finally, on startup one day, he saw a progress bar that would complete and then the device would shut down. Initial Symptom: My husband's Mac had been randomly shutting down for some time, but we were limping it along. If your Mac is unable to access that feature, this may not work for you, but I included some other handy stuff, like recovering files from the drive. NOTE: This process only worked because the hard drive was still able to access recovery mode by holding Command+R on startup. Please use Common sense if I did this and look around the screen for something that looks like what I'm talking about. I did most of this from memory, so I may have messed up a label here or there. This is probably overkill on instructions, but there are PC people out there who may try to help out the (much more) rare critical Mac issue. Hopefully I diagnosed a bad hard drive correctly (I'll provide my method) and I hope this helps someone out there. Being a 1 Mac household and an IT professional who has only supported PCs, I had a challenging time trying to figure out how to reload OSX after my husband's Mac hard drive died.

Internal hard drive for macbook air