mac external hard drive not showing up in disk utility

Click the hard drive that reported the error, click the “First Aid” tab, and now click on “Repair Disk”Īfter Repair Disk has ran successfully, you are free to boot OS X as normal and the drives issues should be resolved.Ī few final notes: relying on a hard drive being healthy is not an alternative to having backups, you need to backup your Mac with regularity using Time Machine or some other method if you choose.

Choose “Disk Utility” from the Mac OS X Utilities screen.

Select “Recovery HD” from the boot menu.

Reboot the Mac and hold down Command+R (hold own Option key on some Macs).

In this case all you need to do is reboot into the Recovery HD partition and run Repair Disk from there, here’s how to do that in Modern MacOS versions including macOS Sierra, High Sierra, Mac OS X El Capitan, Mavericks, Yosemite, OS X Lion, Mountain Lion, and OS X Mavericks.īefore proceeding it’s a good idea to backup your drive quickly with Time Machine.

How to Repair a Boot Disk with Disk Utility That doesn’t mean you can’t repair the boot drive though, it just requires an additional step which we’ll cover next. If you do see a red message saying something along the lines of “Error: This disk needs to be repaired” you can just choose to click the “Repair Disk” button to start that repair process, that will work for any internal or external drive – unless the drive in question is your boot disk, then you will find the “Repair Disk” button is inaccessible. Verifying partition map for “APPLE Media”Ĭhecking the EFI system partition’s file systemĬhecking all HFS data partition loader spacesĬhecking Core Storage Physical Volume partitions Disk Utility should resemble something like the following screen shot:įor the vast majority of users, what you see will look something like this, finalizing with a message of “The partition map appears to be OK”, indicating that no errors have been found: You will find the window populating with messages about the drives health, messages that indicate things are fine appear in black, messages that indicate something is wrong appears in red.

Click on “Verify Disk” in the lower right corner and let it run.

Select the Mac hard drive from the left side menu and click on the “First Aid” tab.

Launch Disk Utility, found within the /Applications/Utilities folder.

Mac external hard drive not showing up in disk utility