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

johnckendall: I found it on apple.com support downloads about ten pages in.

Thanks, yeah, I had found it there but it wouldn't download (was returning the web page not found error). However, later that night when I tried (around 8p edt) it showed up and I was able to get it.

Unfortunately, after installing it and applying the kext's, no joy. Still got freezes. And my temps are all in the high 30's low 40's (celcius).

Waiting on the 10.5 disks from my dad to come in the mail. Figured it can't hurt to try that!

Finally contacted Apple Phone Support again because I am desperate to get this graphics problem resolved so that I can sell my iMac with a clear conscience (and buy a new one?). I've been running 10.6.7 with 10.6.2 kext fix for months now, but I know as soon as someone allowed the system to autoupdate the crashes would return. Anyway, the first tech rep (good cop) was receptive and did seem to think that replacing the video card would be the way to go, but he would have to check with his supervisor. The supervisor (bad cop?) asked a few questions (including if I had zeroed out the hard drive before I reinstalled the OS -- which I in fact have) before asking for a link to this thread and saying that he would forward it on to his engineers. Fingers crossed that something will be done about this.

Apple agreed I have a Graphics card issue and have popped my iMac in for a Graphics card replacement.. Also fingers crossed that I have a usable machine in a few days...

Did they ask you to provide information about the kext fix, or did you simply describe the freezing problem? I have taken my iMac in twice (while it was still under Applecare) and since they could not reproduce the problem during their hardware testing they said there was nothing they could do.

I described the crashing and went through a number of troubleshooting procedures with apple on the phone and then an apple store appointment was made as the issue wasn't resolved. When I got to the apple store we were about to do the same stuff, PRAM, reset SMC or PMU, reboot in safe mode, disk check, permissions etc. Then I mentioned I had screenshots of the first signs of a crash and then the guy said that the graphics card definitly needed replacing and the system fully checking over. It's now in the store so we will see.. I will post summary when it comes back. There is no Kext fix for mine as it's a 9,1 with NVDIA GT130.

After a long time of struggling and being frustrated, I managed Apple to change the GPU of my iMac to a somewhat other revision. I sent in the iMac 24" for three times for service. I phoned a lot with *MANY* apple techs and collected a lot of protocols with the tool, I got from Apple. The GPU change happened about 3 weeks ago and until now there is no freezing any more. The mac is running 10.6.8. without any modifications at the ktext-files. Strange - the apple solutions partner says the new GPU didn't have a different revision number than the replaced one. But the mac is working now for more than 3 weeks without any problem. So it seems, all that people that are suffering same issues (and have left a little bit of guarantee time) should urge Apple to change the GPU. Crossing my finger to have a worthy and wealthy system again.

Message was edited by: michaeljaekel

crinfante and photomatt, please let us know if the new GPU card resolves your screen freezes -- I also would like a fix that would allow me to sell the iMac in good faith. Unfortunately no more applecare, so I'd have to pay for the card myself.

However, I can report GREAT SUCCESS using KrzysiuTurek's "KEXT" replacement fix in conjunction with running 10.6.8 in 64-bit mode on my 24" iMac 8,1 with ATI Radeon HD 2600 Pro.

For 13 days there have been absolutely no more screen freezes or system hangs. No kernel panics. Prior to replacing the ATI KEXT files, I was getting one to three screen freeze / unresponsive system events almost every day. I'm pretty sure now that the kext replacement has eliminated the problem, but I'll report back it returns!

I'm so grateful to KrzysiuTurek for figuring out this work-around, and to so many of you who tried it and reported back. I was feeling like I'd have to junk this beautiful machine.

This for the benefit of newcomers to the thread:

My machine:

Mac 8,1 (24" Alu iMac, "Early 2008"), 2.8 GHz Core 2 Duo processor, ATI Radeon HD 2600 Pro, running Mac OS X 10.6.8 (latest Snow Leopard). Apple Hardware Test (extended) shows no hardware problems. Ha.

What it did:

At seemingly-random times, the screen would go black, or gray, or striped, or remain "frozen" displaying whatever happened to be on-screen at the time. Sometimes a small snippet of music or sound effect would repeat over and over without stopping. No mouse or keyboard input had any effect. I would have to hold the power button for 10 seconds to completely power off the machine.

What I did:

Set OS X to run in 64 bit mode by using "sudo systemsetup -setkernelbootarchitecture x86_64" (google for more info and to check your machine is capable). Then I followed the instructions here: http://krzysztof-turek.com/apple/ to preplace the 10.6.8 ATI graphics "drivers" with the corresponding versions from 10.6.2. Then rebooted. And no more screen freezes!

According to this discussion thread, replacing the kext files has stopped similar problems for quite a number of people, but also there have been a few (two? more?) who have replaced the GPU graphics card and thereby solved the problem without the kext fix. So it appears to me that this is a hardware problem, and is somehow masked or not triggered by the 10.6.2 ATI kexts but is brought out with any later versions (including Lion, unfortunately). Someone correct me if I'm wrong...

Hi Brian,

for me the GPU change worked perfect - see my posting just one before yours. Before changing the GPU I did all the steps you did.

Michael

Michael -- heh heh, I got too wordy and missed yours till I posted mine! Was the GPU an ATI 2600? Any idea what it would have cost you if Apple hadn't covered it? No apple care on mine, unfortnately.

Brian -- No Idea for the costs. I'm a lucky guy (a least this time) and have a apple care with 3 month left. And YES - it is an ATI Radeon 2600.

But I think, it can't be tooo expensive. Just changing the chip. Should be worth to have a well running iMac again.

I solved 2 years of headaches with screen pixalating and freezing on my 24" iMac -GeForce GT 130 graphics card by downloading a free app called FAN CONTROL FOR MAC. It will increase the fan speed and allow the mac to run cooler.( After downloading, it appears in your preferences, not your applications.)

I have not had a freeze in 3 weeks. I'm not sure how it works- it just does.

Eclipsethegalaxy -- I did use this tool too, but:

1. I'm not willing to accept a hairdryer on my desktop
2. I think, this shouldn't be the way to solve this problem
3. AND MOST IMPORTANT: I still suffered some freezes even with fan controll running

Michael

I have an iMac 7,1; 24-inch 2.8GHz; RadeonHD2600; 6 GB OTC memory; currently running 10.6.8. I've had the freeze problem ever since I installed 10.6.3. I've run every test known to man, found ASD 3S116 and tested for days. Found an intermittent graphic adapter error with Tech Tool Pro, but only one time. Found non-fatal HDD error through ASD. I did a cold reinstall of Snow Leopard, and a total restore from Time Machine; still had freezes. Froze during startup, and anytime after, in any app. Since any hardware problem was very intermittent, and only once or twice a month, I focused more on the software side of things. Being an ex-SYSADMIN on HP, Sun & Dell servers, I poured over the syslogs with a fine tooth comb, and started fixing everything I could find, even if it was quoted as informational. Did this for about 30 days straight. Removed eveything Google - Google showed up almost every error I saw in the Console. Reinstalled apps that needed Google. I use Little Snitch, and removed all rules for any software package that wasn't Apple. I wanted to reassign rules very selectively; checked the IP of every app that used the internet. I did nothing else - did not do any KEXT reloads, and I keep current with what Apple sends out. I make sure I check my major packages (Microsoft Office, Adobe CS5, iLife) are up to date at least weekly. Good News - I have not had a freeze at all for the past 45 days - and I used to have 6 or 7 freezes a day. I do not believe the freeze issue is a hardware issue - Apple introduced some new software in 10.6.3 that was probably in alpha status for Lion, and it got inserted in 10.6.3, and Snow Leopard wasn't ready for it. I say I don't believe it is a hardware issue (for the iMac 7,1) because it started in 10.6.3 - wasn't there in 10.6.2. I have not installed Lion yet because I have a critical application that runs in Parallels 5 and I wasn't going to upgrade Parallels (I don't agree with their business model that requires paid upgrades instead of free updates within major releases - but that's another issue). I'm at the point where I can stop using Parallels 5, all of my other software is up to date, and I may just go ahear and upgrade to Lion. But for right now, I've happy with 10.6.8 and no freezes.

For my iMac 8,1 with ATI Radeon HD 2600 Pro I did a complete wipe of my hard drive, zeroed out. Then I reinstalled the OS only and updated to 10.6.7 with a combo updater. Freezes happened until I copied over the 10.6.2 kext files a couple of months ago. Since then no problems, so for my iMac I can't see it being anything other than a driver issue. Perhaps there is a problem with my particular build of GPU?

My specs:

iMac 8,1

ATI Radeon HD 2600 Pro

Vendor: ATI (0x1002)

Device ID: 0x9583

Revision ID: 0x0000

ROM Revision: 113-B2250L-259

EFI Driver Version: 01.00.259

OS 10.6.7 with 10.6.2 kext files

Still waiting to hear from Apple.