Previous 1 2 3 4 Next 54 Replies Latest reply: Dec 1, 2012 1:41 PM by Arosebud0 Branched to a new discussion.
vsserafim Level 1 Level 1 (0 points)

After upgrading my iMac to Mountain Lion it is freezing at least one a day. Sometimes the screen get messed up right before getting frozen, something like this video (from another guy), but they move from top to bottom to me.


I never had this problem before, it started right after the Mountain Lion upgrade.


Anyone with the same problem? Any ideas?

iMac, OS X Mountain Lion, Mountain Lion Server installed
  • Carolyn Samit Level 10 Level 10 (101,790 points)

    I've never seen that before... 


    Check your settings in System Preferences > Accessibility

  • vsserafim Level 1 Level 1 (0 points)

    Hi Carolyn,


    What should I look for in System Preferences > Accessibility?

  • Carolyn Samit Level 10 Level 10 (101,790 points)

    Try Keyboard and Mouse...


    What application is running when your iMac freezes?

  • mende1 Level 10 Level 10 (91,910 points)

    Hold Shift key in boot and use it. It deletes temporary data

  • vsserafim Level 1 Level 1 (0 points)

    From Safari to Pages, Keynote, Aperture, Mail, iTunes, Message,.... you name it. Doesn't seems to have a pattern.

  • vsserafim Level 1 Level 1 (0 points)

    Ok mende1, I did it. I will wait one or two days then I'll report back to all of you.


    Thanks for the tip.

  • vsserafim Level 1 Level 1 (0 points)

    Ok, things are getting worst!!! After sometime working my iMac got in sleep mode. When I got back to work on it the screen was completely black and I'd tried a cold restart. Surprise, surprise: I hear the usual DVD drive sound from the boot and nothing else, just a completely black screen. The iMac is on for sure, cause if I hold the power button for some seconds I can hear it shutting down.


    Never had anything like this until I upgraded to Mountain Lion.


    Now I really need some help!

  • WilfridSellars Level 1 Level 1 (0 points)

    My iMac is doing the exact same thing. If I'm running multiple applications, randomly the whole system will freeze. The only way to restart is to do a hard restart. This has only been happening since I installed Mountain Lion. This occurs roughly once a day. Any suggestions?

  • calebfrom84042 Level 2 Level 2 (355 points)

    Permissions Repair:

    Go to applications then to the "other" folder then go to disk utility, on the left hand side you will see a white box.  Select the second option, usually called "mac HD" with that selected click on "repair permissions" in the center towards the bottom of the screen.  Wait for it to complete, then see if this fixes the issue.



    PRAM Reset:

    1- Ensure the machine is powered off.

    2- Locate the following keys on your keyboard in preparation for Step 4:

    ‘command’ – ‘option’ – ‘P’ – ‘R’

    3- Press the ‘power on’ button.

    4- Immediately – and before the grey screen appears – hold down ‘command-option-P-R’ all together.

    5- Keep them held down until you’ve heard the start-up chime twice. After you release them you should hear it again, and hopefully your Mac will boot up normally

  • WilfridSellars Level 1 Level 1 (0 points)



    Thanks for the tip. I ran the verify permissions and there were lots of reported problems. Then I ran the permissions repair, and now all is fixed. I also did the PRAM reset. Thanks I check to see if this fixes my freeze problem!


    Very much appreciate the help!

  • spumoni Level 1 Level 1 (20 points)

    I feel your pain. I have the same problem. It started immediately after installing Mountain lion. And I had no problems before that.


    I get constant beachballs and stalls.  They can happen at any time. I can't play a QuickTime file without freezing every few seconds.  The freezes last over a minute. And I get stalls when using the Finder, Safari and Chrome. Sometimes my MacBook Pro won't even boot.  The gear below the gray apple just keeps spinning for minutes without ever progressing.  And even when my machine boots, the booting is very slow.


    I've tried fixing permissions.  Booting from a thumb drive and repairing my disk (which it needed.)  Reinstalling Mountain Lion from the app store.  Nothing helps.  I will try resetting PRAM and report back if that helps.


    Here's my only possible clue as to what's wrong.  The information window for my hard drive shows incorrect information.  It shows 639 GB total capacity.  That's okay.  That is the correct capacity.  Then it shows 1 TB available!   You can't have 1 TB of space still available on a 640 GB hard drive that is more than half full.  I have no idea if this is related to my stall problem.


    I'll be watching here for any suggestions.  They will be gratefully accepted.

  • garethhart Level 1 Level 1 (0 points)

    I am having the same issue and it is driving me crazy. There is no pattern to it and the only way I can get around the issue is by holding the power button down till the machine switches off, unplugging it, plugging it back in the powering up again. Not good for the iMac but no option. Apple PLEASE help!

  • resmonde Level 1 Level 1 (0 points)

    Similar problem here on a 2007 iMac recently upgraded from 10.7 to Mountain Lion.  It was not an issue before.


    Almost every day now I come back to find my machine 'sleeping' , or so it seems. 


    But when I try to wake it by mouse movement, I discover a fixed unmoving mouse pointer.  Keyboard input doesn't help either.  The machine is frozen.  I have to shut down the iMac and restart for things to be back to normal.


    Let's hope it's something Apple can fix with an update.

  • SteamPunk Level 1 Level 1 (0 points)

    Same problem here.


    iMac freezes; cursor moves, music still playing but nothing else responds - only way out is power off/on.

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