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

YMarkY wrote:
Another one here with the freeze issues. I'm running 10.6.3 and would like to revert back to 10.6.2. If I just put in my Snow Leopard DVD can I just upgrade from that without losing data? I'm not sure what all will get wiped out on a reinstall.

I was worried about this too. Here's what happened when I reinstalled from the DVD:
My iMac was combo updated to 10.6.4. When I put my retail Snow Leopard 10.6.3 DVD in, booted from it (holding down c key), and installed 10.6.3 again, my user accounts, 3rd party apps (e.g. Office 2008) and most (all?) of my preferences remained.

R C-R wrote:
That isn't what I said. I only advised you to keep in mind that many users are not having any issues with the updates. What Apple does or doesn't officially recognize has nothing to do with it. There are many thousands of posts in various Discussions forums from users running 10.6.3 or later that make no mention of screen freezes or any similar issues. This is also part of the 'knowledge is power' thing that should not be missed.

Yes, fortunately most users are not having issues with these updates. But some users are definitely having problems. It's a frustrating issue also, making further research wanted.

Another thing that should not be missed is that doing a clean install & stopping at 10.6.2 does not demonstrate an intrinsic problem with 10.6.3 or beyond, even for users having freezing problems with the later updates. Some users find that a clean install & applying all available updates solves their problems. Some do not. There must be a reason for this but I do not think ignoring either the users with no problem to begin with or those that have solved theirs is the way to find it.

I've had more contact with Apple today en they suggested doing the things you're discouraging.

Of course, that is just my opinion….

Long live freedom of speech! Anyway, I'm not putting more energy in this discussion.

I'll keep other users updated on how Apple is handling this issue.

I've had more contact with Apple today en they suggested doing the things you're discouraging.

Talking with Apple (hopefully) means their suggestions are applicable for your specific circumstances, considering everything you have already tried so far. This does not mean they would make the same suggestions for every other user.

One reason this is such a frustrating issue is there is no best "one size fits all" solution for it.

YMarkY wrote:
Another one here with the freeze issues. I'm running 10.6.3 and would like to revert back to 10.6.2. If I just put in my Snow Leopard DVD can I just upgrade from that without losing data? I'm not sure what all will get wiped out on a reinstall.

Preliminary results are showing that 10.6.2 might have no or less black screen issues. You could revert back to 10.6.2 if you prefer a reliable iMac on short term. It's my personal opinion this isn't an ideal solution, but downgrading is an intermediate solution while the issue is investigated and until Apple pushes a final fix.

I do have a time capsule with backups.

Looks pretty safe, but exercise on your own risk! Please contact an Apple Authorized Service Provider when in doubt.

My wife's iMac went black again today after being OK for a few days after zapping the PRAM. And it is so interminably that I am worried about bringing it in, as they may not see it unless they use it for an hour or two.

Well I got my iMac back from Apple this afternoon. I was doubtful that they could duplicate my flickering freeze issue, since it took a week between freezes, but they called me a day later saying they saw it. 3 days later my iMac had a new LCD display and cable,inverter power. Been running for 7 hours no problem. Will report back if the flickering returns.

Good luck to all

raccc wrote:
Well I got my iMac back from Apple this afternoon. I was doubtful that they could duplicate my flickering freeze issue, since it took a week between freezes, but they called me a day later saying they saw it. 3 days later my iMac had a new LCD display and cable,inverter power. Been running for 7 hours no problem. Will report back if the flickering returns.

Good luck to all

I hope your problem is solved, but I really don't think the freeze issue is hardware related.

raccc wrote:
Well I got my iMac back from Apple this afternoon. I was doubtful that they could duplicate my flickering freeze issue, since it took a week between freezes, but they called me a day later saying they saw it. 3 days later my iMac had a new LCD display and cable,inverter power. Been running for 7 hours no problem. Will report back if the flickering returns.

Thumbs up, this is great news!

Message was edited by: tommie_c

just found this thread my 2006 imac 24" has starting doing these strange screen/graphic issues since 10.6.4 I have the upgraded nvida 7600GT video card

catch me up here folks what can I do to help this? anything I can do other than somehow go back to 10.6.2?

It can't hurt to run the Apple Hardware Test. (See Apple Hardware Test: iMac (Mid 2007) and later models or Intel-based Macs: Using Apple Hardware Test for the details.) Note that it cannot detect every hardware issue, especially intermittent ones, but if it finds anything wrong you will know it needs service.

Note also that even if the iMac runs 10.6.2 fine, that does not necessarily mean there is nothing wrong with the hardware. Every version of the OS uses the hardware slightly differently & one usage pattern may reveal a fault in it that another won't, at least until it gets worse.

I have a G5 iMac like that: I started getting occasional random display anomalies in its behavior that at first were much more frequent when running 10.5 than 10.4, but eventually would show up with any OS version. Oddly, they don't show up at all in Classic mode windows when I run OS 9 applications using Tiger. Go figure.

Some users report using a third party utility to speed up the fans helps, but this is basically a bandaid, not a permanent cure.

Hi everyone.
Just a few words: I managed to get rid of random lockups by disabling Little Snitch network monitor and disabling 3D acceleration for VMware Fusion guests.

Further investigation with stackshot confirmed that there is something weird going on with OpenGL: WindowServer gets stuck somewhere inside ATIRadeonX2000GLDriver.bundle (my iMac has a Radeon HD2400), while some processes are caught in a deadlock on _CGSSynchronizeWindowBackingStore (one of which was always Little Snitch UI Agent).

IMHO, a feasible workaround would be forcibly switching off Quartz Extreme and staying out of OpenGL's way until Apple releases a fix.
I'm not entirely sure to whom I should file a bugreport, though 🙂

(PS: sorry for my bad english!)

Message was edited by: morpho - some typos here and there...

Ooops, wrong post, please kill it 🙂

Message was edited by: morpho

I have an iMac 8,1 (ATI Radeon HD 2600) and after the 10.6.3 update... it just started to freeze. ¬¬ What a shame. I bought this mac because I thought that macs are more stable. But... now I realize that mac are just computers like PCs that can crash any time.

Unfortunately, any computer can crash if it loads its OS from a mutable source like a hard drive because that source can be corrupted. Long ago, very simple OS's were locked into ROM chips in personal computers like Commodore 64's. They were extremely stable but the only way to update the OS (such as it was) was to buy a new set of chips & replace the old ones. With modern OS's weighing in at several GB & so complex that there is essentially zero chance that they are 100% bug free, this is obviously not a practical alternative.

The closest we get to an immutable OS in the Mac world is loading it from a read only source like a DVD, for example the installer discs that come with Macs. But the price for this is not being able to save any new files or file changes to that source; including system & network settings, preferences, logs, references, & of course updates to the OS.

That makes it unsuitable for daily use but very useful for restoring the mutable copy of the OS to a known stable state -- as long as we don't allow anything from the old mutable source that might destabilize it back into it afterwards. Since this is both inconvenient & hard to do -- who wants to go through everything in a backup file by file or even knows everything to look for? -- there is no way to guarantee that a Mac's OS is 100% stable once we start using it.

Scrap my last comment, I just got a full blown kernel panic: page fault in kernel mode.
Guess who was the culprit: com.apple.ATIRadeonX2000.

(Yes, I ran AHT, I NEVER saw a panic on this machine and - to be honest - ruling out faulty RAM a page fault in kernel mode is hardly a hardware problem...)