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

KTurek at one point posted a URL containing a download of the KExts:

http://blog.krzysztof-turek.com/apple-imac-8-1-freeze-problem-solution-en/

If you can't find them there, I also have a copy that I can put in my Dropbox.

Also, I have an iMac 7,1 that was giving me the exact trouble described in this thread until I installed the KExt fix; I had left it at 10.6.7 with the KExt fix installed until about a month ago, when I upgraded to 10.7.4.  Since the upgrade to 10.7.4, I have not had a return of the freezing behavior.

Hi geychaner - Just checking, you upgraded to 10.7.4 and it works without the kext file fix? I also have the iMac 7,1 and I'm hanging with 10.7.2 and just didn't want to go through it all again.

Let me know and thanks!

Yes, I upgraded to 10.7.4 and did not reinstall the KExt fix. I checked the versions of the relevant KExt files, and they are the correct Lion versions, not the old (6.0.6?) versions used with the KExt fix. I jumped straight to 10.7.4 when I finally had to bite the bullet and go to iCloud.

I upgraded to 10.7.4 at the beginning of June. About a week in I had a complete system shutdown (which is not what I was experiencing before, I had the freezes) and rather than take any chances, I did the Kext fix.  Has been fine since, keeping my fingers crossed.

That's interesting. I'll be interested to see what other people encountered jumpting to 10.74. I see Marno49 had some trouble, but it doesn't sound like it was the same issue. If I wasn't so busy trying to get work done, this wouldn't be such a hassle.

Thanks for both of the replies. Anyone else want to chime in on the 10.7.4 upgrade?

I have now 10.7.4 and as you know iMac 8.1. The problem with 10.7.4 in my case is strange becouse i make kext fix TWICE before it works. At first time it simply don't work - after week youtube flash player kill's my machine.

@geychaner and KrzysiuTurek

Hi thanks so much, I downloaded the files with no problem.

I was on a paralell thread because I have a 20" imac, not a 24" so I missed all the talk and have been reading this one but was still on page 20...

Great job KrzysiuTurek! So let me check, in my case I can use these files with my model, right?

    ATI2400controller.kext

    ATIFramebuffer.kext

    ATISupport.kext

----> And when I upgrade to Lion I have to repeat the process all over again?

In detail:

I have an aluminum 20-inch iMac 7.1 OSX 2.0Ghz intel Core 2Duo, from August 2007 now running last updates of SL 10.6.8 with an ATI Radeon HD 2400 XT.

Although I still have the problem (since 2010) now it does not happen so often, oddly since I started preventing my imac from entering sleep and keep time machine off and back up manually. Or maybe because I don't handle large files anymore as I mostly work with code...but it is still random just like opening chrome and scroll down and get the freeze.

If you can confirm that these are the right kext. files for me I'll back up and try the fix.

Glad to know that 10.7.4 seems fine for 7,1inch macs but I'll follow this thread to see how it goes before I do so. Hope we'll not be here still by 2015 trying to fix this...

@CarlaBlue

I have a different machine and graphics card from you.  I have iMac 8,1 with ATI Radeon HD 2600 Pro.  However, I've read somewhere on this thread that users running 10.6.8 and the kext fix MUST run in 64-bit mode (and not 32-bit mode) to avoid kernel panics.  I am not absolutely sure this applies to iMac 7,1 with Radeon HD 2400 XT, but maybe it does, so you should look into this.

BTW I'm running 10.6.8 in 64-bit mode, and KrzysiuTurek's  "kext fix" has saved my machine from the junk heap!  Good luck.

Thanks Brian, I was just thinking about that now because I am running in 32-bit mode, but if it works for me if I change for 64-bit I still have to check first if all my apps are able to run in 64-bits. I'll wait and see if I get an answer about it on my post above.

I haven't rechecked this, but I seem to recall that 64-bit mode here refers to the operating system and not apps. If I'm correct in that, a 32-bit app would still be able to run.

Praise be, KrzysiuTurek. I seem to have got my iMac back. After months of dithering, I finally plucked up enough courage -- or desperation -- to apply your kexts fix. And after two days of running Mail, iCal, Chrome, Photoshop and InDesign simultaneously the machine hasn't crashed or frozen yet.

I did try this once before, but must have done so carelessly (it was, as I remember, almost the middle of the night). So I then had to reinstall the OS from scratch. But this time, touch wood, 10.7.4 is running smoothly and continuously -- without, , as far as I'm concerned, any mode change.

So thanks again. And shame on Apple for not owning up to the problem and issuing the fix themselves...

dmaude, do you have the same imac model as I do, I guess?

Could you please tell me what is your model?

Because if it is the same then I'll save myself some time and upgrade directly to 10.7.4 and then if it freezes I'll apply the kexts fix and see if I can join the other happy people here.

My model is an aluminum 20-inch iMac 7.1 OSX 2.0Ghz intel Core 2Duo, from August 2007 with an ATI Radeon HD 2400 XT.

@TK111 thanks for the tip, I'm glad to know that

This is the same model iMac as mine. I started using the kext fix way back in 10.6.3 and it's worked flawlessly since.

Great news Vurey, can you tell me just some last things?

When you did it with snow leopard you changed from running 32-bit to 64-bit? And I should do that before or after apllying the fix?

And are you running 10.7 now? It is just because I want to be practical and upgrade already so as I don't have to do the fix twice, first for 10.6.8 and then for 10.7.thanks

@CarlaBlue, -- Regarding 10.6.8 and 64-bit mode:  TK111 is right, we're talking about booting the OS to run in 64-bit mode.  You don't have to change any apps.  32-bit apps will still run fine.   I first changed to boot into 64 bit mode, and ran that way for a few days to see if any problems occurred (there were none), then applied the "kext fix". 

To make my machine boot into 64-bit mode every time, I used a "defaults write" Terminal command.  I think you can easily find it with google...

I believe 10.7 (alll versions) run in 64-bit mode by default, so that's why you don't have to do anything special before applying the kext fix in 10.7.