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

dmaude

If you read my post a few back there are 3 types kernel architecture utilized by Macs. But at the time in SN 10.6.2 when the working kext where written there where only 2 kernel architectures utilized in Macs(that I know of) i386 and x86-64. Straight 64 is different than x86-64 and taking no special steps to boot 64 happens because it is the default for 10.8, 10.9 & 10.10. At least for me in Mavericks telling my 7,1iMac(exact same as yours) to boot in x86-64 and not the 64 has resulted in zero freezes. I just haven't made the leap to 10.10. But since you have and are still having freezes running 10.10 with the terminal command:

sudo nvram boot-args=“kext-dev-mode=1

Try telling the kernel to boot in x86-64 not 64 with the command:

sudo systemsetup -setkernelbootarchitecture x86_64

Please post back if has worked or if you have found another solution.

I expressed myself badly. The sentence "I now seem to have got it back" was intended to indicate that, thanks to your detailed instructions and the helpful contributions of others, I've had no freezes since persuading Yosemite to load the old kexts. But I'll keep your kernel boot mode instruction in reserve, just in case. Thanks again, to all, for a machine that works for me - and doesn't provoke desperate calls from my wife, whenever she tries to use it, of "aargh, it's done it again!"

After a month without any freeze with the AMD kext from 10.9.5 I had two freeze yesterday, apply the 10.6.2 kext for my imac 7,1 and deleting the AMD and all works fine again.

I also want to THANK the people who found the solution to this problem from OS X 10.6.3 to Yosemite and the people who shared their experiences in this thread. Without this thread I wouldn't be able to use the newest OS X om my iMac.

iMac 8,1:

When you update to Yosemite 10.10.1 you need to apply the "kext fix" again and the "kext-dev-mode=1" fix to prevent the imac to freeze.

I have a 20-inch mid-2007 iMac with an ATI Radeon HD 2400 XT graphics card.

It is currently running Mountain Lion.

I speak very little English.

What are they the "Keys" to be destroyed?
What are they the arguments to put in the file with "com.apple.Boot.plist"

Thanks,

I had a similar experience to Tazthed with the 10.1.1. The freezes came back almost immediately, but the update left the three previously installed ATI kexts in place -- they just didn't load. All I had to do was remove the three AMD ones and run "kext-dev-mode=1" in Terminal.

I'm getting really sick of applying this fix every update, so I finally posted a bug report to Apple on both their developer site and at the OS X feedback page here: http://www.apple.com/feedback/macosx.html

I encourage everyone else to do this as well. It might not help, but it certainly won't hurt!

Twedie

if you want to update to mavericks and need assistance with tutorial feel free to contact me. That said I have no experience with Mt. Lion I skipped over it completely.

Thanks swmaster,

I've been dutifully deleting and installing the kext fixes for a number of years (21+ updates?) on my early 2008 24" iMac. It's always worked flawlessly until the latest 10.10.1 where the kext fix put it into something that felt like a weird safe mode. I did your sudo nvram boot-args="kext-dev-mode=1" worked a treat so now I'm back in business.

Here were the symptoms in case someone else with the same problem is searching...

After 10.10.1 update via app store:

Screen started its freezing tricks including beach ball cursor that doesn't do anything except move around.

After kext fix:

- Screen went very bright and brightness keys did nothing

- In System Preferences/Displays, no brightness slider and I tried to calibrate colours but able to change anything and it thought I had a 31" screen.

- Screen movement sluggish and slow to redraw windows, delays to scroll in windows, cursor went under bar at top of some windows. I could still close the window if I placed the cursor where the red dot "should" have been.

- Names of dock programs wouldn't show up if I moved the cursor between them.

After repair permissions:

- No improvement

After your kext-dev-mode=1

- All good.

I actually got a response to the bug report I made on Apple's Developer Bug Reporter (I'm not a developer so I'm surprised I could make one at all)! Here's what they wrote:

Please provide sysdiagnose output when you see this again. Please collect sysdiagnose while the problem is occurring or as soon as possible afterwards.

You can use a key command to start sysdiagnose, or use a terminal command.

Using a key command:

1. Press Shift-Control-Option-Command-Period when the issue reproduces

2. Wait for a few minutes (you can release the keys).

3. When sysdiagnose has completed (may take several minutes), a Finder window will open up showing the new sysdiagnose file in /var/tmp. Attach that file to the bug report. You can also manually locate the new sysdiagnose file in /var/tmp or /private/var/tmp, and upload that file.

Using the terminal:

1. Launch Terminal.app

2. Enter this command: sudo sysdiagnose

3. Enter your admin password

4. When sysdiagnose has completed (may take several minutes), a Finder window will open up showing the new sysdiagnose file in /var/tmp. Attach that file to the bug report. You can also manually locate the new sysdiagnose file in /var/tmp or /private/var/tmp, and upload that file.

I don't think that I can do this because when it freezes, I think the whole machine is non-responsive. Does anyone know if the OS is still functioning when the screen goes black or some other funky color? With the fix applied, this isn't likely to happen again until the next update for me. I don't know how I could do anything with the sysdiagnose file anyway since I can't see the Finder window pop up. If I could get some useful info though, I'd love to! Any thoughts?

In my case the machine still works, just misses the screen (graphics card). With the failure I've been able to connect to the iMac and access via SSH to turn it off correctly, not taking away the tension.

The keyboard may work and can launch the sysdiagnose, but nothing will appear on the screen. The second option may be more feasible.

I do not think that after so many years doing nothing Apple, now does, but you can try.

Tazthed and swmaster,

thanks for the tip on the "kext-dev-mode=1" in the "com.apple.Boot.plist" file.

As I am not very familiar with Terminal do you mind posting detailed instructions on how to edit?

Thanks a lot!

Hey, folks. Does the report below make anyone think that Apple still does not know how to write drivers for its graphics cards?

http://appleinsider.com/articles/14/12/30/apples-latest-mac-pro-continues-to-cau se-problems-for-professional-users

Note that the Windows drivers for these Mac Pro computers work fine, as indicated by the stability of the machines under Boot Camp. Way, way back in this email thread on iMacs, someone indicated that the same was true regarding our machines. So Windows has a driver that addresses the problem, whereas OS X users do not.

Is anyone concerned about buying, say, an expensive Retina iMac and finding out a year or so down the road - after an OS upgrade - that the drivers make the computer freeze up? Anyone want the solution to be booting into Windows?

Guys, this can be fixed with a firmware update.

https://discussions.apple.com/thread...t=660&tstart=0

Read that, and force the firmware update onto your GPU with either FreeDOS or Linux.

No need to hack with old drivers.