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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 swmaster,

    swmaster swmaster Oct 18, 2014 1:51 AM in response to Daniel Smith-Weiss
    Level 1 (0 points)
    Oct 18, 2014 1:51 AM in response to Daniel Smith-Weiss

    mine just froze.

    the old kexts will not load, cause Yosemite has kext signature checking enabled, and the 10.6.2

    ones obviously have no valid signature. so if you remove the new AMDxxxx kexts you are left

    with sw only graphics, which is painfully jerky.

     

    disabling kext signatures is possible, i just did this, and the old kexts booted perfectly.

     

    you have to edit this file: /Library/Preferences/SystemConfiguration/com.apple.Boot.plist

     

    there is a "Kernel Flags" key, and an empty <string></string> value. you have to type

    kext-dev-mode=1 between the string markers, and save the file. to do so, you require administrative

    credentials. it can be done from terminal, but a regular text editor works as well.

     

    don't you screw up the file, or your mac may not be able to boot easily.

    depending your current configuration or hardware, the file may contains other sections, whatsoever.

    those need to be left intact.

     

    warning: this stuff disables osx10.10's kext security measures, so basically any proper kext can

    be loaded. yes, even ones, that contain malicious code or stuff like that. so choose your kexts

    wisely. nevertheless, there wasn't any kext-security before yosemite anyway.

     

    Should you not have the original files from 10.6.2., there's an easy way to extract them from the

    apple system updates as long they are available for download.

  • by swmaster,

    swmaster swmaster Oct 18, 2014 2:13 AM in response to swmaster
    Level 1 (0 points)
    Oct 18, 2014 2:13 AM in response to swmaster

    the boot file:

     

    $ cat /Library/Preferences/SystemConfiguration/com.apple.Boot.plist

    <?xml version="1.0" encoding="UTF-8"?>

    <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">

    <plist version="1.0">

    <dict>

      <key>Kernel Flags</key>

      <string>kext-dev-mode=1</string>

    </dict>

    </plist>

    os version:

    $ uname -a

    Darwin crowley.local 14.0.0 Darwin Kernel Version 14.0.0: Fri Sep 19 00:26:44 PDT 2014; root:xnu-2782.1.97~2/RELEASE_X86_64 x86_64

     

    loaded kexts:

    $ kextstat | egrep 'ATI|AMD'

      104    2 0xffffff7f8222f000 0x45000    0x45000    com.apple.kext.ATISupport (6.0.6) <66 12 11 7 5 4 3 1>

      105    0 0xffffff7f82274000 0xca000    0xca000    com.apple.kext.ATI2400Controller (6.0.6) <104 66 12 11 5 4 3 1>

      106    0 0xffffff7f81850000 0x233000   0x233000   com.apple.ATIRadeonX2000 (10.0.0) <66 12 7 6 5 4 3 1>

      108    0 0xffffff7f8233e000 0x12000    0x12000    com.apple.kext.ATIFramebuffer (6.0.6) <104 66 12 11 7 5 4 3 1>

  • by Tazthed,

    Tazthed Tazthed Oct 18, 2014 6:55 AM in response to swmaster
    Level 1 (0 points)
    Oct 18, 2014 6:55 AM in response to swmaster

    swmaster: Thank you for your post.

     

    Can you see if this is correct - I want to make it easy for others.

     

    1) Install Yosemite OS X.

     

    2) Install the 3 original kext ATI files from 10.6.2 with the Kext Helper.

     

    3) Edit this file: /Library/Preferences/SystemConfiguration/com.apple.Boot.plist


    by typing:

    kext-dev-mode=1

    between the <string></string> markers, so it looks like this:

    <dict>

      <key>Kernel Flags</key>

      <string>kext-dev-mode=1</string>

    </dict>

     

    4) Save the plist file.


    5) Reboot your computer. Done!

     

    -------------------------

     

    Question: what does "kext-dev-mode=1" mean?

     


  • by swmaster,

    swmaster swmaster Oct 18, 2014 8:42 AM in response to Tazthed
    Level 1 (0 points)
    Oct 18, 2014 8:42 AM in response to Tazthed

    Hi Tazthed,

    yes, you nailed it. this is the process.

    kext-dev-mode=1 enables to load unsigned kexts, thus the old ones we (or better said our oldie radeon 2x00s) like :-)

     

    i'm quite sure someone will just put together a click-click app for all this.

     

    one note though: as it is owned by root (and shall remain so), 3rd party editors from app store may not be able

    to modify it. for example textwrangler fails if you try to save anything that requires admin password, like this

    file. this is a rule enforced by the app store. you can read more about this here:

    http://www.textwrangler.com/support/bbedit/auth-saves.html

     

    TextEdit even refuses to open the file.

     

    so the easiest way for a bit experienced users is to do this via Terminal and sudo+vi.

  • by Tazthed,

    Tazthed Tazthed Oct 18, 2014 8:54 AM in response to swmaster
    Level 1 (0 points)
    Oct 18, 2014 8:54 AM in response to swmaster

    Okay thanks swmaster ;-)

     

    It sounds complicated with the Terminal. I hope that someday someone will find an easier solution to his freezing issue on Yosemite.

  • by swmaster,

    swmaster swmaster Oct 18, 2014 8:54 AM in response to swmaster
    Level 1 (0 points)
    Oct 18, 2014 8:54 AM in response to swmaster

    just checked, there's a one-liner, which does the trick:

     

    open Terminal, and type at the prompt:

    sudo nvram boot-args="kext-dev-mode=1"

     

    OSX will prompt for your password, enter it, characters will not be echoed in Terminal.

     

    then close Terminal and reboot, and you are good to go.

    this does not modify the above mentioned file (com.apple.Boot.plist), it does the modification in the nvram.

    but the result is the same.

  • by Tazthed,

    Tazthed Tazthed Oct 18, 2014 11:06 AM in response to swmaster
    Level 1 (0 points)
    Oct 18, 2014 11:06 AM in response to swmaster

    Cool! I will try it when I have made a backup and installed Yosemite. Thanks swmaster!

  • by TeardropCarnival,

    TeardropCarnival TeardropCarnival Oct 20, 2014 4:28 PM in response to Tazthed
    Level 1 (0 points)
    Oct 20, 2014 4:28 PM in response to Tazthed

    I have been a long follower of this thread.

    I have a mid-2007 20-inch iMac that has been suffering from this issue for many years now. Mine is best described as the freezing issue where the mouse still moves and audio keeps playing but nothing else can be done without a hard reset.

    Up until recently I had been applying the kext fix successfully to remedy the problem.

     

    I decided to investigate Yosemite's effect on the issue..

     

    I was pleasantly surprised to find that after installing 10.10 I had zero freezes for a several days. I never used to make it more than a couple minutes after rebooting. Mind you, my iMac is no longer my main system and now only works under a very light load (web browsing, video streaming, etc). However, today I tried plugging in an external bus powered firewire drive. After mounting the drive and then opening an audio software program, my system froze for the first time under Yosemite.

     

    It was at that point that I took the usual steps and applied the kext fix, deleted the AMD extensions, and edited the com.apple.Boot.plist file (which was a new step for me).

     

    The first issue I noticed after the kext fix was very laggy and choppy picture quality. The mouse movements weren't smooth and everything seemed to struggle. After applying the "kext-dev-mode=1" fix and rebooting, the lag seemed to be resolved. However, I ultimately ended up losing my 2nd display via the midi-DVI connection as well as finding several small display issues such as: no program names showing up when you hover over the icons in the dock, choppy text and icons in stacks in the dock, and some other less than desirable side effects.

     

    Needless to say, this was unacceptable performance to me so I re-installed Yosemite and now things are back to normal. Until I push the system harder I suppose..

     

    Obviously this is only my experience, but I felt I should share it with you all since we're still in the early stages of Yosemite with the freezing issue and only a few of us have tested it. Clearly the problem persists so any feedback is welcomed.

  • by mattwinters78,

    mattwinters78 mattwinters78 Oct 21, 2014 9:05 AM in response to TeardropCarnival
    Level 1 (0 points)
    Oct 21, 2014 9:05 AM in response to TeardropCarnival

    7,1 here with 10.9.5 running no freezes. you must run sudo command in terminal to permanently boot in 64-bit run the delete all AMD kexts install ati kexts from 10.6.2. A good fan control is recommend because card still runs warm.

  • by karlfromshoreview,

    karlfromshoreview karlfromshoreview Oct 22, 2014 7:22 AM in response to mattwinters78
    Level 1 (4 points)
    iPad
    Oct 22, 2014 7:22 AM in response to mattwinters78

    I've been suffering with the screen freeze ever since my 2006 iMac Apple Care warranty expired (and even before ... but Apple never acknowledged the ATI driver issue; just kept telling me to reload the operating system).  Anyway, I have been late in learning that Apple is replacing video cards on 2011-2012 27 inch iMacs with a similar problem affecting the ATI video card. ( iMac (27-inch): AMD Radeon 6970M Video Card Replacement Program )  I have been shopping for a new 27" iMac but am now hesitating.  Is anyone willing to speculate if there will be a recurrence of these problems with the newest generation of iMacs since Apple never seems to have been able to root out the cause in several earlier generations?

  • by Kwong Kian Tew,

    Kwong Kian Tew Kwong Kian Tew Oct 22, 2014 6:50 PM in response to Kwong Kian Tew
    Level 1 (70 points)
    Oct 22, 2014 6:50 PM in response to Kwong Kian Tew

    Previously I reported that I had not freezes after upgrading to 10.9.5 and using the stock kexts, unfortunately after a week or so it started to freeze for a handful of times in about 1 month. I noticed that each instance happened when I was using safari.

     

    I have just upgraded to 10.10 and still using the stock kexts, so far no freezes for just 1 day so it is still too early to confirm.

     

    I am using an early 2008 iMac with ATI Radeon HD 2600Pro, ROM Revision: 113-B2250L-259

  • by santitf,

    santitf santitf Oct 24, 2014 5:04 AM in response to Hugo_Loureiro
    Level 1 (0 points)
    Oct 24, 2014 5:04 AM in response to Hugo_Loureiro

    Hi!

    2 weeks without fixing the kexts from 10.6.2 and my imac 2007 has no freeze in 10.9.5.

    And yes, my system load the AMD2400Controller, AMDFramebuffer and AMDSupport

  • by mattwinters78,

    mattwinters78 mattwinters78 Oct 25, 2014 8:51 PM in response to santitf
    Level 1 (0 points)
    Oct 25, 2014 8:51 PM in response to santitf

    I have been running Mavericks 10.9.5 on a iMac 7,1 Core 2 Dou 2.0Ghz 4G Ram for nearly a month with the fix I have created simply by using bits and peaces I have found through out the last 112 pages of this thread. I have created a very detailed tutorial for all those affected iMacs with the ATI 2400 & ATI 2600 Graphics card. Sorry I tried several times to post here but the formating and apple support forum kept timing out on me here.

    Go see attachment here:

     

    http://forums.macrumors.com/showthread.php?t=1809500

  • by mattwinters78,

    mattwinters78 mattwinters78 Oct 27, 2014 9:25 PM in response to mattwinters78
    Level 1 (0 points)
    Oct 27, 2014 9:25 PM in response to mattwinters78

    STEP-BY-STEP GUIDE TO APPLY THE ATI KEXT FIX FOR 7,1iMacs 8,1iMacs & “VINTAGE” MACS THAT SILL HAVE FREEZES WITH THE ATI GRAPHIC KEXTS FROM 10.6.2 RUNNING ON OSX v10.9.5 MAVERICKS

    I want to thank all those involved certainly Krysztof Turek for finding the original 10.6.2 kext fix. Other honorable mentions Freandc, aieronimo & TK111. I want to thank Freandc for writing most of this. I have changed some of the wording to assist with the 7,1iMac some 8,1iMacs and other “Vintage” Macs. who still experience freezes in Mavericks. Follow this procedure to get the Krysztof Turek Kext Fix solution to work on older “Vintage” Macs running OS X 10.9.5

    Subsequently additional updates to OS X may require the following procedure to be repeated or a portion thereof.

    • Usually just removing new AMD kext installed with update

    After Updating to Mavericks 10.9.5

    1.Download Cindori Kext Drop here:

    2.Download the 10.6..2 ATI kexts here:

    3.Use Apple Menu->About This Mac and click the “More Info” button to determine which version of the ATI Radeon Card is installed.

    • I have only had direct experience with the  ATI 2400 in a iMac7,1.
    • I believe Freandc has direct experience with the ATI 2600 in a iMac8,1 (Freandc if I'm wrong correct me)
    • Both the ATI2400 & ATI2600 were available in iMac 7,1 & iMac 8,1 among other Macs

    4.I recommend logging in as root user so all changes will be systemwide.

    • To learn how to login as root user go here:
    • http://support.apple.com/kb/PH14281
    • CAUTION!!! Any changes made as root user not mentioned here may damage machine.
    • Logout and login in as root user.

    5.Those who are experimenting this fix with other cards pay close attention as you may still have other kext that are needed to operate your graphics card.

    • Mavericks has renamed the ATI kexts to AMD kexts .
    • REMOVE ALL the AMD kexts to a safe backup location NOT JUST COPY from here:
    • /System/Library/Extensions
    • Kexts will load alphabetically and the AMD kexts will load before the ATI kexts if not REMOVED.
    • If you have the affected ATI 2400 & ATI 2600 graphics card there is still one ATI kext (ATIRadeonX2000) that loads.
    • There are known problems related to it please leave the ATIRadeonX2000 kext installed.
      • LION USERS REMOVE all ATI kexts from /System/Library/Extensions folder except for the ATIRadeonX2000 kext.

    6.Run Cindori Kext Drop downloaded in STEP 1 and drag the kexts downloaded in STEP 2 into the primary text area.

    • The kexts you want are:
      • ATIFramebuffer.kext
      • ATISupport.kext
      • ATIxxxxController.kext -->(where xxxx refers to the type of card you have)
    • Click install and enter your password where indicated.

    7.The 7,1 iMac, some 8,1 iMacs & other Vintage Macs that are capable booting the kernel  in 64-bit, but whose kernel boots in 32-bit  by default when v10.6(snow leopard) was/is the OSX. I implore you to test my theory in step 8 which may help those early iMac who have the 10.6.2 kexts installed in Mavericks and are still experiencing the freezes.

    • SKIP TO STEP 9 Only if your Mac boots the kernel in 64-bit by default while running OSX v10.6
    • If you're unsure which kernel your Mac boots while running v10.6 go here:
    • If your Mac is not on the list then it boots the kernel by default in 32-bit while running v10.6
    • To see why the kexts will or will not load dependent on the kernel go here:

    8.Mavericks already boots the kernel in 64-bit and the 10.6.2 kexts released by Krysztof Turek are supposed to run in a 64-bit environment but I believe that these older Macs fail to load all or a portion of the 10.6.2 kexts in Mavericks.

    • The solution that has worked for me is to tell the EFI to boot the kernel in 64-bit mode by running the terminal command:

    sudo systemsetup -setkernelbootarchitecture x86_64

    • Hit enter and close terminal
    • I realize in Mavericks the kernel already boots in 64-bit by default but the terminal command given modifies: /Library/Preferences/SystemConfiguration/com.apple.Boot.plist with the following kernel flag:
      • <string>x86_64</string>
        • It and will take effect every time you start up from this disk.
        • If you start up from a different disk, the default setting on that disk will take effect.
    • To remove the kernel flag simply navigate to /Library/Preferences/SystemConfiguration/com.apple.Boot.plist and delete the x86_64 between the string markers.
    • I know there are other ways to tell the EFI to boot 64-bit while running OSX v10.6(such as holding down “6” and “4” key while booting but this is required every time you boot up the machine and thus not very convenient).
      • I don’t know if the are other ways that still have same outcome.
        • If other ways produce the same outcome work then they may be useful to YOSEMITE USERS who use the same Boot.plist with the kernel flag below which allows unsigned kext to be used.
          • <string>kext-dev-mode=1</string>
            • YOSEMITE USERS please see Question C at end of tutorial.

    9.Reboot and Login in as REGULAR USER and DISABLE!!!! ROOT USER

    To confirm changes have taken place:

    ALL USERS

    • Go to "Apple Menu"-->Click "About This Mac"-->Click "More info"-->Click”system Report"
      • On the left hand panes list of components select-->Software-->Extension
      • Locate the ATI kexts you should see all three kexts and their loaded status should say yes.
      • And the version number for the three that were installed should be 1.6.6
    • In addition to the three kexts you have installed some users may see:
      • ATIRadeonX2000 kext has loaded with a different version number
        • I believe this ATI kext is still updated by Apple and I would leave it along.
        • To this date there is no issue with the ATIRadeonX2000 kext running on the system.

    EFI 32-bit USERS who had to follow STEP 8 to boot the EFI in 64-bit kernel permanently.

    • Go to:
      • /Library/Preferences/SystemConfiguration/com.apple.Boot.plist
        • To confirm the change has taken place the plist should appear as:
          • <string>x86_64</string>
    • If the solution has worked for you please post with your Mac model, Graphics Card model & OSX Version you tested on

    QUESTIONS I STILL HAVE FOR ANY OF YOU OUT THERE

    Please reply to this post with your:

    • Answer to questions A,B or C, your Mac model, Graphics Card model & OSX Version

    A.Can any other iMac, MacBook, Mac Mini or MacBook Air users confirm that the theory has worked for you?

    B.Has someone found this theory to work with Graphics Card Freezes other than the ATI 2400 or 2600 cards.

    C.YOSEMITE USERS Does the Terminal command code which allows the loading of unsigned kexts in Yosemite work in conjunction with the kernel flag implemented in my theory?

    • If so what does that Boot.plist looks like if they work in conjunction and how to implement them.
    • Or does the Kernal flag:   <string>kext-dev-mode=1</string>   do the same thing as the theory in step 8?

    D.Does anyone know what bearing the ATIRadeonX2000 kext has on ATI 2400 & 2600 cards?

    • If so. Do other ATI kext still load on other machines? i.e.other affected Graphics Card Freezes theory may helped prevent freezes.
  • by mattwinters78,

    mattwinters78 mattwinters78 Oct 28, 2014 10:16 AM in response to swmaster
    Level 1 (0 points)
    Oct 28, 2014 10:16 AM in response to swmaster

    Swmaster

    Does adding the kext-dev-mode=1 between the string markers allow OSX v.10.9.5(mavericks) or other OSX that will normally only load 64-bit kext to use 32-bit kext?

    As this may answer my Question C. in the tutorial above.

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