4 Replies Latest reply: Feb 5, 2013 8:21 PM by Garth Brown
Garth Brown Level 1 (15 points)

The last two times I tried to rebuild OS X Mountain Lion the system seemed to hang at about the 1/3 mark on the progress bar. On both occasions I let the rebuild run overnight only to see the bar stuck where I left it. Is this an indication that I need to reinstall the OS?

Mac Pro (Early 2008), OS X Mountain Lion (10.8.2)
  • Barney-15E Level 8 (46,274 points)

    What are you "rebuilding?"
    I don't understand what you mean by that term.


    Can you explain a bit more explicitly what you are doing?

  • Garth Brown Level 1 (15 points)

    When I start my Mac I hold down the Shift key, which opens the OS in "Safe" mode and, in the process, "rebuilds." What that rebuild entails is a mystery to me. It may be optimizing file storage. It may repairing permissions. It may be repairing the disk. It may be doing some or all of the above and much more. Who knows. All I know is that in the past it has corrected any number problems I've encountered using the Mac OS and permitted me to continue working.


    Most recently, however, the rebuild process hangs. Not an encouraging sign.


    Thanks for your interest.

  • g_wolfman Level 4 (1,120 points)

    The progress bar appears during a directory check of the startup volume.  Which is apparently not working correctly.


    You should boot into your recovery partition and verify the disk.  It may be failing.  Or there may be unrecoverable volume errors, in which case reinstallation of the OS or a tool like Disk Warrior may be in order (although really, these days Disk Warrior is kind of overkill if you don't need to recover data from a partially failed disk...since reinstalling the OS is so easy and doesn't touch your user data).

  • Garth Brown Level 1 (15 points)

    Thanks for the explanation and suggestion.