Check Hard Drive Health of a Mac with Disk Utility

It’s a good idea to check the hard drive health of a Mac as part of a periodic maintenance routine. Doing this is extremely easy with Disk Utility, here’s how to do it and what to do if you encounter any issues:
- Launch Disk Utility, found within the /Applications/Utilities folder
- Select the Mac hard drive from the left side menu and click on the “First Aid” tab
- Click on “Verify Disk” in the lower right corner and let it run
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. For the vast majority of users it will look something like this, finalizing with a message of “The partition map appears to be OK”, indicating no errors:
Verifying partition map for “APPLE Media”
Checking prerequisites
Checking the partition list
Checking for an EFI system partition
Checking the EFI system partition’s size
Checking the EFI system partition’s file system
Checking all HFS data partition loader spaces
Checking Core Storage Physical Volume partitions
The partition map appears to be OK
If you do see a red message saying something along the lines of “Error: This disk needs to be repaired” and it’s your boot drive, you’ll find the “Repair Disk” button is inaccessible. 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 OS X Lion and Mountain Lion:
Before proceeding it’s a good idea to backup your drive quickly with Time Machine.
- Reboot the Mac and hold down Command+R (hold own Option key on some Macs)
- Select “Recovery HD” from the boot menu
- Choose “Disk Utility” from the Mac OS X Utilities screen
- Click the hard drive that reported the error, click the “First Aid” tab, and now click on “Repair Disk”
After Repair Disk has ran successfully, you are free to boot OS X as normal and the drives issues should be resolved.
A 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. Hard drives fail, it’s a fact of computing life. It’s also important to note Disk Utility isn’t a 100% conclusive test suite to determine drive health, and if you hear weird sounds coming out of the hard drive it’s probably a good time to head down to Apple and prepare for a drive swap because that drive is likely going to croak soon.









