I'm a MacBook user and I had previously installed Windows on my laptop.

After deleting the Windows partition now, I'm facing difficulty in expanding my hard drive partition to the maximum. After I drag the the partition to Full and click Apply, it shows:

Checking journaled HFS+ volume

Then, a message pops out:

Partition failed with the error : couldn't modify partition map because file system verification failed.

What should I do?

2 Answers 2


Try this:

  1. Reboot the Mac into Single User Mode by holding ⌘ (Command) + S when pressing the power button.
  2. When the command prompt finally appears, type: /sbin/fsck - fy
  3. After this is completed, type reboot or exit.
  4. Wait for Mac to start up normally.
  5. Back in Disk Utility, hit Verify Disk, then try and partition as normal.
  • 1
    support.apple.com/kb/ts1417 says that "If you're using Mac OS X 10.4 or later, you should use Disk Utility instead of fsck, whenever possible".
    – Lri
    Jul 29, 2013 at 14:51

Simply Hold Shift before startup. This brings the mac into safe mode and it checks the system for errors. Then try modifying the partition again.

  • It just verifies or repairs the startup volume (the partition like Macintosh HD), which can also be done from Disk Utility.
    – Lri
    Jul 29, 2013 at 14:57
  • Disk utility is UNABLE to repair the volume because it's the startup volume. Going into safe mode checks and Repairs any errors on the drive as well
    – jw382
    Jul 29, 2013 at 15:24
  • Disk Utility does allow repairing the startup volume if you start up from a recovery partition or installation disk. When I tried starting up in safe mode with verbose mode enabled, it only seemed to check the Macintosh HD volume and not the drive.
    – Lri
    Jul 29, 2013 at 15:35

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