Repair Boot Disk in Mac OS X with Disk Utility & Recovery HD
If you have tried to repair the boot volume before in Mac OS X before, you’ll undoubtedly have found the “Repair Disk” option is grey and unavailable within the Disk Utility tool. While this is still the case while booted in most versions of OS X, you can repair the Mac OS X boot disk thanks to OS X’s Recovery Partition, preventing the need from using an external boot drive to repair the disk.
The trick is to boot the Mac into Recovery Mode first, and run the Repair function from there. Once booted into Recovery mode you’ll find the limitations on Disk Utility’s repair function has been removed, and you can go about repairing the boot disk as intended. We’ll cover exactly how to do this, step by step.
How to Repair a Mac Boot Disk with Disk Utility in OS X
- Reboot the Mac and hold down Command+R to boot into Recovery, or hold down OPTION
- Select “Recovery HD” at the boot menu
- At the Mac OS X Utilities screen, select “Disk Utility”
- Select the boot volume or partition from the left menu and click on the “Repair” tab
- Repair Disk is now possible, click on “Repair Disk” to repair the boot volume
The repair process can take a while if there are a lot of errors on the drive, but oftentimes there are no problems found and so there will be nothing performed. The best thing to do is let the process run it’s course, as it may take a while and you don’t want to interrupt either the initial scanning for drive problems, or the repair attempts assuming any issues have been discovered on the drive.
While you’re in Recovery mode, you may also want to verify disk permissions and repair them, repair user permissions, and verify and repair other disks as well.
Again, if you see that the “Repair Disk” function is greyed out and not clickable in Disk Utility, be sure to boot back into Recovery Mode again on the Mac to make it accessible again.
Do keep in mind that “Verify Disk” will always be available, whether booted from the primary startup volume or not, it’s only the Repair function which, on newer versions of OS X, requires the usage from a recovery disk or another startup disk on the Mac.