Q: System Freezes Randomly after 10.6.3 Update

Yep, I had a particularly bad day yesterday. I had so many frustrating mouse freezes, I used my PC instead. The horror. Apple better start paying attention if they want to keep their customers. First this mouse freezing problem, and then not acknowledging the iphone 4 serious antenna design flaw. Jobs says "just hold it differently". REALLY BAD.... tsk tsk.

Stan Fisher wrote:
Noticing that most of the contributors on this page are running 10.6.4, I just red Apple's description of the .4 update, which was to fix the very issue we all have encountered. I guess you're saying it doesn't work? I've just reverted to 6.1, unaware of the 6.4 update, from 10.6.3. It took my iMac two tries to recognize the install DVD. As with at least one other, my machine would freeze, in that no folders etc could be accessed, but the mouse moved freely; after 5 minutes or so, it "fixed" itself.

Hi Stan,

Which part of the 10.6.4 description were you thinking addresses this issue?
http://support.apple.com/kb/ht4150
I saw this line: "resolves an issue that causes the keyboard or trackpad to become unresponsive", but that seemed to be missing the part about mouse clicks also being unresponsive, and the display being frozen.

Also, in your case, "after 5 minutes or so, it 'fixed' itself." In my case (and others), the display never unfreezes, even after hours of waiting. I wonder if we have two different issues caused by something unrelated. In my case the mouse pointer can continue to be moved, many background processes (that don't try to change the contents of the screen) continue to run, but the keyboard does nothing, nor does clicking on anything on the screen with the mouse. If I ssh into the "frozen" iMac (model 7,1), and use the "top" command, the WindowServer process is "stuck". The only way I've been able to unfreeze my iMac is to reboot it remotely or by forcing it to shutdown (I hold the power button for 5 secs).

I would also note that this issue never occurred under 10.5.8. I went directly to 10.6.3 since that's what was on the Snow Leopard retail DVD I purchased. The problem started happening in 10.6.3, and 10.6.4 Combo update did not fix it. I've installed from the DVD twice, reset PRAM, reset the power mgr, made sure all my apps are up to date (I don't use any funky plugins or input managers) - nothing has helped.

This is really getting frustrating - my poor 11 year old daughter lost a bunch of school work when the iMac froze on her (she was using PowerPoint 2008). I warned her to save often, but even every 5 minutes was not enough for her to lose a couple slides worth. She won't work on that machine anymore (it's one of the fastest in our house).

mert:

I know you said that your apps are up to date & that you don't use any "funky plugins" or input managers, but what is in your menu bar, to the left of the Spotlight icon? This is the area for items like the menu bar clock, the fast user switching menu, Time Machine menu, etc.

There are two kinds of items that might be there that look alike but are different:

• *Menu Extras*, which can be moved by a command + click & drag. They always appear to the right of any status items
• *Status Items*, which can't be moved. They always appear to the left of any menu extras.

Apple provides 26 possible menu extras, all found in /System/Library/CoreServices/Menu Extras, each with the extension ".menu." These are the only menu extras Apple supports. Any others can only be installed by hacking the OS, often without users' knowledge by the installer that creates them. There quite a few third party menu extras available, including many popular or highly rated ones, that do this, so it is a good idea to check for their presence in your menu bar.

Status items are OK; it is third party menu extras to watch out for. Do not trust any supplied documentation to tell you about this; perform a command+drag "wiggle test" to see if they are movable. If they are, they are menu extras.

The problem with these things is that they rely on private, undocumented API's Apple reserves for its use alone & unlike status items run in system space. These API's can & often do change from one version of the OS to another. Thus, their presence in your system (either during or after an OS update) can destabilize it & cause seemingly unrelated problems.

If you have any of these things installed in your system, that could be the cause of your problems.

R C-R wrote:
mert:

I know you said that your apps are up to date & that you don't use any "funky plugins" or input managers, but what is in your menu bar, to the left of the Spotlight icon? This is the area for items like the menu bar clock, the fast user switching menu, Time Machine menu, etc.

Only Apple stuff: Fast User Switching, Volume, Clock, Time Machine status, iSync (or MobileMe?) status.

Has anyone tried something like copying the video drivers (kernel extensions) from, say, 10.6.2 and run them on a 10.6.4 system. I don't have access to a 10.6.2 system to try this. I'm not even sure I could figure how to do it. I also don't pretend to know if this would even be possible or have a prayer of working. For all I know, the system may not even boot in such a configuration, or it may become even more unstable than now. Just a thought.

Why do I mention video drivers? Simple - that's what appears to freeze (in my case).

(By the way, as I mentioned earlier in this thread - I've also run Apple's Extended Hardware Tests in looping mode overnight and it found no problems with my machine.)

mert wrote:
Why do I mention video drivers? Simple - that's what appears to freeze (in my case).

I thought you said that the underlying problem on your Mac was that WindowServer got "stuck." WindowServer is not a video driver. As explained in the "Quartz Compositor" section of Mac OS X Technology Overview: Graphics and Multimedia Technologies, it coordinates window behavior, composites windows on the Desktop, & has other functions, but it is basically the layer that mediates between the actual hardware drivers & the graphics renderers. It also handles certain keystrokes & other user input, dispatching it to the appropriate process for the window the input event occurred in.

IOW, anything at either "end" of the WindowServer layer, or some problem within it, could be causing the WindowServer process to hang.

R C-R wrote:

mert wrote:
Why do I mention video drivers? Simple - that's what appears to freeze (in my case).

I thought you said that the underlying problem on your Mac was that WindowServer got "stuck." WindowServer is not a video driver. As explained in the "Quartz Compositor" section of Mac OS X Technology Overview: Graphics and Multimedia Technologies, it coordinates window behavior, composites windows on the Desktop, & has other functions, but it is basically the layer that mediates between the actual hardware drivers & the graphics renderers. It also handles certain keystrokes & other user input, dispatching it to the appropriate process for the window the input event occurred in.

IOW, anything at either "end" of the WindowServer layer, or some problem within it, could be causing the WindowServer process to hang.

I know the WindowServer is not the hardware driver. However, if the driver locks up, couldn't that possibly lock up the WindowServer process, seeing how it's "the layer that mediates between the actual hardware drivers & the graphics renderers".

However, if the driver locks up, couldn't that possibly lock up the WindowServer process …

Yes it could, but so could a problem in the rendering layers or possibly even in the user input event queue WindowServer reads to dispatch events to windowed processes. If you visualize it in building block terms like in the diagram (fig 3-1) in the technology overview article, the problem could be 'above' or 'below' WindowServer, or even within WindowServer itself.

R C-R wrote:

However, if the driver locks up, couldn't that possibly lock up the WindowServer process …

Yes it could, but so could a problem in the rendering layers or possibly even in the user input event queue WindowServer reads to dispatch events to windowed processes. If you visualize it in building block terms like in the diagram (fig 3-1) in the technology overview article, the problem could be 'above' or 'below' WindowServer, or even within WindowServer itself.

Yes - it could be anything related to the WindowServer or the WindowServer itself, or something entirely different. We've talked about and tried lots of other ideas. I don't recall anyone attempting to change-out just the driver. Why not start with the drivers since that is something I've read about being swapped out individually in attempts to fix other problems in the past (on earlier version of OS X). It's (drivers) also something Apple has made fixes to in past to correct problems.

Message was edited by: mert

Why not start with the drivers since that is something I've read about being swapped out individually in attempts to fix other problems in the past (on earlier version of OS X).

Mostly because drivers, other system extensions, & their supporting files are made to be used together as a set, not mixed together piecemeal from different OS versions. In fact, there are few if any stand-alone, self-contained drivers in OS X. Essentially all of them fit somewhere in a hierarchic "family," with different parts providing different functionality, often to several different types of "children."

Counting plugins, bundles, & package contents, I would guess at least 25 & probably closer to 50 files in /System/Library/Extensions in some way supply a part of graphics driver functionality. With that many dependencies, fixing one problem by swapping pieces from another version is very likely to cause other problems, maybe much bigger ones.

R C-R wrote:
fixing one problem by swapping pieces from another version is very likely to cause other problems, maybe much bigger ones.

I agree that it's not much of a solution to revert back to older kexts, even if it may seem it's part of the problem, it may very well not be.
I do however like how you put it here RCR, for IMHO, it doesn't seem possible to have a bigger problem than a non workable unreliable iMac since the release of 10.6.3 upwards. 10.6.2, still no problems, stable to work with. 10.6.3 without anything installed, will freeze (everything visible, mouse cursor moving, but frozen otherwise, must force reboot with button) after a couple of hours of idling without any third-party software installed. 10.6.4 as well. Any OS below 10.6.3 does not reproduce the freeze.

I'm so disappointed in the efforts apple has put into this (by acknowledging this problem by posting an update that addresses these issues).

I really hope that all people in this forum religiously keep posting bug reports until something is done about this, as apple DOES NOT pick up on the problem from these user forums. Post bug reports here: http://www.apple.com/feedback/macosx.html

To me the biggest possible problem would be anything that resulted in the destruction or corruption of my already saved files, including those on any attached backup disks like Time Machine or clone ones. Since just about every driver has some dependency on the I/O Kit, including graphics & video drivers, it isn't impossible a mismatched graphics or video driver could cause this kind of problem, & that I would learn about it after it was too late to do anything about it.

So I suggest that if you are temped to try this, it would be a very good idea to take the precaution of having an offline backup of at least your important user files before doing so.

And not to beat a dead horse, but since most users do not seem to behaving these random freeze issues with 10.6.3 & beyond, something as yet undiscovered unique to the systems that do must be at fault. This makes it very important to send Apple as much info about your system as possible in your bug report, which should be done via http://www.apple.com/feedback/ unless you are a member of the Developer Connection.

For the same reason, it is important to include what info you can in posts here, including public profile items like location & an unambiguous description of your Mac model. (For instance "iMac" doesn't tell us much but "iMac 8.1" does.)

After reading 28 pages of denials that there's a problem, I'm going to add that my iMac 8,1 suffers from this freezing problem with 10.6.3 & 10.6.4. First the screen freezes though the mouse cursor can still be moved, then the green screen of death, followed by a hard reboot.

For me, it's 10.6.2 until Apple finally comes up with a solution for this.

OK, I would like to share some more information regarding this problem. I have the freeze problems in 10.6.3 and 10.6.4 too on my iMac7,1. I tried several things and here are some results:

- I'm using both Ethernet and Wifi connection (from the same TimeCapsule). It seems that the type of network connection influences the bug behavior. When I install e.g. 10.6.4 Combo Update when the iMac is connected via Ethernet then I have quite many freezes when connected via Ethernet. But when I unplug the Ethernet cable and start using Wifi the number of freezes is significantly lower. Tried both ways and works via versa.

- Most often (but not always) system freezes while playing a video or working with Aperture

- I had problems with freezing the screen only (the picture was frozen) except the mouse was moving. After reinstalling the 10.6.4 Combo update I have different type of freezes - the screen becomes black

- SSH and VNC (!!!) are working while the screen is frozen. System can be restarted via VNC or SSH command (sudo shutdown -r now). I can continue working on my computer via VNC ... very strange.

- I don't know if it is relevant, but when I installed 10.6.3 update I also switched from Asus router to Apple TimeCapsule - from that time I'm experiencing this problem

- I tried to uninstall all strange applications. I cleaned everything from the top bar (close to spotlight), I cleaned the startup, I uninstalled all Adobe products, I updated all applications to the latest version, I uninstalled all plug-ins (Perian, Flip4Mac, Growl) and reinstalled Perian only in current version - BUT NO SUCCESS

I switched from Win to Mac some years before because of these unexpected freezes in Windows and I was happy that I have Mac that doesn't have this kind of problems. But now it behaves worse than Windows and the last update didn't fix it. Next step will be viruses on Mac and then we should quit using computers and return back to the nature :)))

I want to go back to 10.6.2. My retail DVD has 10.6.3 on it. I'm currently polling some friends in search of a retail DVD with a version of 10.6 that's older than 10.6.3.

Assuming I get my hands on a retail Snow Leopard DVD with 10.6.0 (or 10.6.1 or 10.6.2), will I have lots/any issues if I just boot from the DVD and tell it to install ( not erase install)? Then, if necessary, Combo-update to 10.6.2. This seemed to work fine when I tried a reinstall and my hard drive had 10.6.4 on it (it put 10.6.3 back on the drive).

I'm wondering about things like Mail, or iCal, or Contacts, etc. Will they "survive" an OS downgrade from 10.6.4 to 10.6.2 (or 10.6.0 followed by Combo-update to 10.6.2)?