5 Replies Latest reply: Nov 2, 2012 9:35 AM by BDAqua
Alan Kidner Level 1 Level 1 (45 points)

Greetings, I have a 20-inch iMac (Mid 2007, MA876LL, 2.0GHz Intel) that I am trying to return to service.  The computer seems to work fine in safe mode / after a safe boot.  However, if I boot normally it freezes / locks up when the desktop wall paper is displayed and before the login dialog box comes up.

So far I have tried the following steps none of which have helped:
- Repaired the disk permissions
- Applied a fresh disk image to the hard drive (works okay on other iMacs)
- Reset PRAM and NVRAM
- Ran the extended Apple Hardware Test (no faults found)
- Installed and ran AppleJack
- Used remote terminal session to check running processes on 'frozen' computer (as far as I can tell none were stuck, none using too much CPU, none using too much memory)

How reliable is the Apple Hardware Test?  Can anyone suggest what to try next or the next diagnostic steps to take?  Thank you in anticipation of help!

Mac OS X (10.6.7)
  • BDAqua Level 10 Level 10 (120,025 points)

    Hi alan, here's the skinny...


    One way to test is to Safe Boot from the HD, (holding Shift key down at bootup), run Disk Utility in Applications>Utilities, then highlight your drive, click on Repair Permissions, Test for problem in Safe Mode...


    PS. Safe boot may stay on the gray radian for a long time, let it go, it's trying to repair the Hard Drive


    Reboot, test again.


    If it only does it in Regular Boot, then it could be some hardware problem like Video card, (Quartz is turned off in Safe Mode), or Airport, or 3rd party add-on, Check System Preferences>Accounts>Login Items window to see if it or something relevant is listed.


    Check the System Preferences>Other Row, for 3rd party Pref Panes.


    Also look in these if they exist, some are invisible...







  • Alan Kidner Level 1 Level 1 (45 points)

    Thanks for your reply.

    Also look in these if they exist, some are invisible...
    /private/var/run/StartupItems  <<<< does not exist
    /Library/StartupItems              <<<< empty
    /System/Library/StartupItems   <<<< empty
    /System/Library/LaunchDaemons  <<<< lots of items in here
    /Library/LaunchDaemons         <<<< a few items in here

    Can I boot in normal mode with Quartz off to see if the GUI still freezes?  I tried:
    sudo defaults write /Library/Preferences/com.apple.windowserver QuartzGLEnabled -boolean NO
    But I am not sure that this is equivalent to what happens to Quartz during a safe boot!

    When I booted normally it froze again.  A remote terminal session showed WindowServer in a 'stuck' state.

  • BDAqua Level 10 Level 10 (120,025 points)

    Hmmm, I think it uses a whole different driver in Safe Mode.


    Can you boot in to verbose mode...




    Does it happen if you make a new admin user & boot into that account?


    We could eliminate all the...




    files as a problem.

  • Alan Kidner Level 1 Level 1 (45 points)

    Sadly my boss has told me to close the job and put the computer in to store for use as spares.

    Thanks for your help.

  • BDAqua Level 10 Level 10 (120,025 points)

    OK, good luck Alan.