DazzaG

Q: 24" iMac Screen Freezes since 10.6.3 update - pls help!

I don't know if this is just coincidence or not, but since updating my iMac to 10.6.3 it keeps on crashing. On 3 separate occasions today, whilst using my Mac the screen has gone completely black with thin white lines down it.....see pic below:

http://picasaweb.google.com/lh/photo/6SYzhCgVYEU5TBKqRfOQ1Q?feat=directlink

The fans and hard disk are still running but it will not respond to any keyboard or mouse presses - I simply have to turn it off by holding the power button in.
It will then restart as usual.

Anyone got any ideas? Do you think that if I was to re-install Mac OS X from my original install disk it could solve the issue?

Thanks

Darren

24" intel imac 2.8Ghz, Mac OS X (10.6.3)

Posted on Mar 31, 2010 2:43 PM

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Q: 24" iMac Screen Freezes since 10.6.3 update - pls help!

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  • by Lord_Nemesi,

    Lord_Nemesi Lord_Nemesi Aug 18, 2012 8:56 AM in response to CarlaBlue
    Level 1 (0 points)
    Aug 18, 2012 8:56 AM in response to CarlaBlue

    Hi,

    I have an iMac 7,1 (Late 2007) but my problems are little different. My machine freeze only in certain situations:

     

    1) Exploring time machine

    2) Using Top sites in Safari

    3) Play quake live or other games.

     

    I also noticed that my temps are very high compared with yours:

     

    GPU: 69°C

     

    GPU Diode: 72°C

     

    Is there a way to better cool my GPU?

     

    Thanks in advance.

     

    Alessandro

  • by swmaster,

    swmaster swmaster Aug 18, 2012 2:16 PM in response to Mac
    Level 1 (0 points)
    Aug 18, 2012 2:16 PM in response to Mac

    @Mac,

     

    i had the same experience (lagging cursor movement), as i was trying to find out, which of the kexts is really needed. i experimented a bit with various versions (e.g. the latest version from ATISupport and the 10.6.2 ATIFramebuffer and ATI2400Controller).

     

    what it proved to me, if any of those kexts fail to load (ATISupport, ATI2400Controller (or 2600 if you have the better GPU), ATIFramebuffer) - yeah, it can happen if you have inconsistent versions installed - you end up hawing white screen (if unlucky) or very "stroboscopic" mouse movement, and impossible slow reaction when using the GUI.

     

    you should check, what do you have on your iMac using Terminal. just type "kextstat | grep ATI" and you'll be presented a list like this one:

     

    imac:~ swmaster$ kextstat|grep ATI

      103    2 0xffffff7f8165c000 0x46000    0x46000    com.apple.kext.ATISupport (6.0.6) <69 10 9 7 5 4 3 1>

      104    0 0xffffff7f81fa4000 0xca000    0xca000    com.apple.kext.ATI2400Controller (6.0.6) <103 69 10 9 5 4 3 1>

      105    0 0xffffff7f816a9000 0x2cc000   0x2cc000   com.apple.ATIRadeonX2000 (8.0.0) <72 69 10 7 6 5 4 3 1>

      107    0 0xffffff7f8206e000 0x12000    0x12000    com.apple.kext.ATIFramebuffer (6.0.6) <103 69 10 9 7 5 4 3 1>

     

    as you se, i have the most recent version from ATIRadeonX2000 (8.0.0 - it's from mountain lion) you don't mess with that, or you will start getting kernel panics.

     

    the other kexts are version 6.0.6, e.g. from the "last know good" 10.6.2 update.

     

    there are a couple of things you have to pay attention when installing the kexts. it actually doesn't matter, what way you use to install them (the terminal way or the kexthelper way), but at the end you have to make sure

    - all the newly installed kexts are owned by user root and group wheel

    - none of them is writeable by anybody but root

    - none of them has extended attributes

     

    otherwise MacOS will not load them, and you end up with the current issue. "fixing permissions" will do the trick, but it takes time.

     

    kext caches need to be rebuilt properly, otherwise MacOS will boot the old cache with the "non-working" ATI drivers from your recently updated OS version (say 10.6.3+, 10.7+ 10.8+) and you still get the freezes.

    it should happen automatically, as you change anything in the folder "/System/Library/Extensions".

    but it takes time, sometimes a couple of minutes.

    as i experienced, Lion and Mountain Lion automatically delays the shutdown/restart procedure if there is a kext cache rebuilding in progress.

     

    you can check anytime, when your kext cache was rebuilt:

     

    on lion/mountain lion type in terminal:

     

    imac:~ swmaster$ ls -la /System/Library/Caches/com.apple.kext.caches/Startup/kernelcache

     

    on Snowleo it's:

     

    imac:~ swmaster$ ls -la /System/Library/Caches/com.apple.kext.caches/Startup/Extensions.mkext

     

    the file date will tell you what you need to know. mine is ML, and it was built on 29.07 6:18pm

     

    -rw-r--r--  1 root  wheel  15988456 Jul 29 18:18 /System/Library/Caches/com.apple.kext.caches/Startup/kernelcache

     

    it you see, it's not recent (say you rolled back the 10.6.2 drivers today, and the cache is from yesterday), you can force a kext rebuild easily by typing this in Terminal:

     

    imac:~ swmaster$ sudo touch /System/Library/Extensions

     

    kextd will notify it, and automagically start kextcache utility to rebuild the caches. (this works on ML and L, i do not have SL installed anywhere to test this). wait a bit, and re-check the kext cache date using the previously shown way.

     

    hth,

    swmaster

  • by Mac,

    Mac Mac Aug 19, 2012 1:38 PM in response to swmaster
    Level 1 (115 points)
    Aug 19, 2012 1:38 PM in response to swmaster

    Just saw your comments swmaster, and I'm going to follow your instructions and report back ASAP!

  • by Mac,

    Mac Mac Aug 19, 2012 1:47 PM in response to swmaster
    Level 1 (115 points)
    Aug 19, 2012 1:47 PM in response to swmaster

    I just tried the kextstat I grep ATI command and nothing happens. have I mistyped it?

  • by Mac,

    Mac Mac Aug 19, 2012 1:52 PM in response to swmaster
    Level 1 (115 points)
    Aug 19, 2012 1:52 PM in response to swmaster

    You mentioned that it's possible to reinstall the 10.6.2 kextstat via Terminal, perhaps I could try doing that and see if the problem gets resolved, because while my iMac is working in Safe Mode, I'm unable to access kexthelper.

  • by bobzart,

    bobzart bobzart Aug 20, 2012 7:23 AM in response to Mac
    Level 1 (0 points)
    Aug 20, 2012 7:23 AM in response to Mac

    I had experienced kext panics since back in 10.6.2. I read all posts and tried everything. I went so far as replacing my CPU with a 2.8 Intel Core duo chip with no change in crashes. iMac always booted and worked fine in safe mode, indicating software problems. Reading cresh reports indicated a different extension and app each time. I deduced that there must be something common to all failed extensions. I found that font conflicts were ALWAYS involved. In Fontbook I validated fonts to find many "minor" errors. These do not indicate errors in the fonts themselves and often indicate conflicts. I resolved all the conflicts and eliminated Helvetica fractions font which I know from previous posts caused trouble. After 2 years of struggles with many types of screen freezes.  I now have a trouble free (and because of the CPU upgrade) iMac screamer. I called Apple care to inform them of my discovery and they indicated that it was worth looking into. It's an easy fix and worth a try. Good luck all.

  • by Mac,

    Mac Mac Aug 20, 2012 8:11 AM in response to bobzart
    Level 1 (115 points)
    Aug 20, 2012 8:11 AM in response to bobzart

    @bobzart

     

    Could you provide me with a step-by-step walkthrough if possible? I trust it can be done while in safe mode?

     

    Thanks

  • by Mac,

    Mac Mac Aug 20, 2012 8:16 AM in response to Mac
    Level 1 (115 points)
    Aug 20, 2012 8:16 AM in response to Mac

    @bobzart

     

    I've just looked in my fontbook folder and Helvetica Fractions isn't listed.

  • by Mac,

    Mac Mac Aug 21, 2012 3:40 AM in response to Mac
    Level 1 (115 points)
    Aug 21, 2012 3:40 AM in response to Mac

    Just to update, I tried the 10.6.2 Driver rollback process again, and amazingly everything's back to normal! I'm so relieved, and can only hope things continue to remain stable. Thank you to bobzart and swmaster for your efforts. 

  • by aieronimo,

    aieronimo aieronimo Aug 21, 2012 4:30 AM in response to Mac
    Level 1 (0 points)
    Aug 21, 2012 4:30 AM in response to Mac

    Just to clarify:  it is Krzysiu Turek who resolved this problem with the kext fix.  Notwithstanding 81 pages (and counting) of problem descriptions and suggested fixes, his is the only fix that works without a hitch across Snow Leopard, Lion and Mountain Lion.  No offense to others with ideas about fans and fonts and such.  But the definitive solution to this problem - other than paying for a new graphics card for an old computer - goes back more than a year.

  • by Tardigrada,

    Tardigrada Tardigrada Aug 21, 2012 5:44 AM in response to goskip40
    Level 1 (9 points)
    Mac OS X
    Aug 21, 2012 5:44 AM in response to goskip40

    goskip40 wrote:

     

    I used the kext helper which worked cleanly within a few seconds, but the reboot did hang which concerned me a little. I needed to kill the kext helper from the Unix prompt before the system rebooted. After experiencing a hang my heart was in my mouth for a few seconds, but was relived to see it boot properly.

    Yes, Kext Helper always hangs after doing a kext change. I wonder if this was ever fixed. Does someone know who the developer is or if it has a website or something?

  • by dmaude,

    dmaude dmaude Aug 21, 2012 7:11 AM in response to aieronimo
    Level 1 (0 points)
    Aug 21, 2012 7:11 AM in response to aieronimo

    Agreed. And isn't that a scandal for "the world's most valuable company of all time," Tim Cook?

  • by Gr8er,

    Gr8er Gr8er Aug 22, 2012 2:36 AM in response to DazzaG
    Level 1 (0 points)
    Aug 22, 2012 2:36 AM in response to DazzaG

    I know there is a lot of talk about the freezing and such on these forums. I am wondering what people have been doing with their machines that freeze. Are people buying them or can they get fixed?

  • by Roelof2,

    Roelof2 Roelof2 Aug 24, 2012 12:48 AM in response to DazzaG
    Level 1 (0 points)
    Aug 24, 2012 12:48 AM in response to DazzaG

    Apple updated OSX Mountain Lion to 10.8.1.

     

    Did someone install it allready?

    Is it the solution for the freez problem? (Do the 10.6.2 Kext still work?)

     

    Is it possible to store the OSX updates.

    (There will be a point when the 10.6.2 kext will not work anymore!)

  • by KrzysiuTurek,

    KrzysiuTurek KrzysiuTurek Aug 24, 2012 1:05 AM in response to DazzaG
    Level 1 (0 points)
    Aug 24, 2012 1:05 AM in response to DazzaG

    Hi,

     

    I installed 10.8.1 and kext fix still works

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