Q: OSX Lion + 2011 iMac 27'' + Video = Freeze

I haven't bought imac yet (don't think i will).  Anycase when i went to apple store last weekend to check out the display imacs.  i tried the sleep -> video freeze test there in 27" imac.

1. played some youtube video

2. paused the video  in the middle

3. forced the imac to sleep for 1-2 minutes

4. after waking up, i could not continue playing the same video...only that particular tab in safari FROZE!!!!Looks like this is the minor version of what we are discussing here.  Anyways wanted to share this.

I will never buy IMAC till this thread is closed!!!

I will tell you now that this can be fixed with

An osx lion update if they find a cure

I never had one issue with leopard ever!! Until the first

Update that came out on osx lion 10.7.2

Nuff said

Mick,

It's not a faulty video card. 

It's a faulty LION. 

     roar...

Yes Studio K, I know that's almost certainly the case as well, but I guess they have to go through all their motions and exhaust all repair possibilities. Even if they issue you a new machine, I've read posts in this thread that say they just have the same issue on the new machines as well.

As we now all almost certainly know, we need LION to be fixed.

Thanks!

Hmmm...this issue gets weirder and weirder.

Today, I was plugging away when my iMac froze.  I was browsing my iTunes library through my Apple TV at the time, and noticed that the Apple TV was slow, but was still able to browse the library.

Mouse and keyboard on the iMac were non-responsive, but the most recent active window was iTunes, and when I brushed the top of my magic mouse, the left-right scrolling was working and the screen updated.  I still couldn't do anything, because keyboard commands (e.g. force quit) were non-responsive, and if I moved the mouse, the pointer appeared "stuck" where it was, but obviously the system was still running in the background.

I think (for me, at least) this confirms that it's definitely a Lion issue, as it's the UI that's not responding (or maybe the Human Interface Device control), not the entire system.  I don't have another Mac to remotely access my iMac, or I'd give that a shot to see what happens.  Has anyone tried something like that during these freezes?

Oh, and to be clear, I do experience some genuine "system crashes", too.  When those happen, the system tells me it crashed when I restart and asks me to send the crash report to Apple.  Also, I sometimes get a dim screen with white text on it telling me the system needs to be restarted.

Yes SpongeBad, I also noticed that when my iMac "freezes" that I'm still able to browse and view my iTunes library using Plex on my iPad, so the system still seems to be running, but my mouse and keyboard are non-responsive on the iMac, similar to what you're describing using Apple TV.

Also, I noticed that sometimes when the iMac freezes while Time Machine is backing up, that the external HD still seems to be writing data so I'll wait for it to fall silent. Then, after a restart, I'll notice that Time Machine logs a backup time as complete even though it was after the iMac froze.

And like you, sometimes I get genuine crashes and kernel panics.

Yeah every freeze I get it seems the system is still running underneath the frozen UI... I am able to SSH into my iMac and issue a proper shutdown sequence.

Interesting... would you be so kind as to post instructions on how to get into the iMac using SSH? I would much rather do that than punishing my HD with hard resets every time.

Appreciate the help!

Sure, start your iMac and go to System Preferences -> Sharing and check "Remote Login". You should see the hostname you need to use to SSH into your computer in the text on this screen. Then, when your computer freezes, SSH into it from another computer and at the command line type "shutdown -r now" to restart it... it can take a while for it to happen, but it will eventually restart.

I've noticed something interesting today, in trying to narrow down the source of this problem.  I wanted to run a memory test to see if I could find anything odd with the RAM in my system (just in case, because even though it appears to be a software issue with everyone experience it, it "feels" like a hardware issue, and I've had a lot of hardware issues with Macs over the last three years). 

I downloaded and installed Rember, and left it running on the Mac.  The Mac is rock solid when Rember is running, no freezes, no crashes.  When I stopped Rember, the system froze probably about 20-30 minutes later (I wasn't actively using it when it froze).  I decided to restart and run Rember while I worked with the system on-and-off, and it's been running all day with no freezes.

Since the crash logs seem to show an issue with the power management system, I'm wondering if it's happening when the system is trying to put some part to "sleep" (even though I have all the sleep settings turned to "never" right now), and Rember is preventing it from activating that piece of power management software (probably related to the CPU's power management, if that's the case, since it's constantly shuffling things in and out of memory while Rember is running).

Would certainly explain why it's more stable when sleep is turned off.

Anyone else willing to try running Rember in the background and see if it helps them?

SpongeBad,

I'll give it a try next week when I get home from Thanksgiving travels. I will say that as far as sleep issues go, 10.7.1 fixed those for me. Now when my system freezes I get console messages that say GPU Debug followed by thousands of memory value entries similar to "0xFFFFFF38". When I eventually restart the Apple crash notification does not even come up, so I can't even "report" it to Apple.

So you are seeing messages like the ones I posted in this thread ?

https://discussions.apple.com/thread/3366876?start=0&tstart=0

jrey,

Yup, just like you have posted there, every time. Like I said before though, the system is still running underneath the frozen UI as I am able to SSH in. Also in bootcamp I get blue screens of death on Windows 7 related to the AMD gpu drivers. I am so frustrated.

Thanks for the confirmation.   Mine just did it again a few minutes ago.   aarrrggg..

I can SSH and shutdown as well.  

I do not have/use bootcamp.

I have been working about 2 hours this morning, so it is not immediately after coming out of sleep.

Safari was not even loaded at the time.

and down it goes

Nov 26 10:46:21 JRiMac kernel[0]: 0x00000010

Nov 26 10:46:21 JRiMac kernel[0]: 0x00010000

Nov 26 10:46:21 JRiMac kernel[0]: 0x00000017

Nov 26 10:46:21 JRiMac kernel[0]: 0x000000bf

Nov 26 10:46:21 JRiMac kernel[0]: 0x00000000

Nov 26 10:46:21 JRiMac kernel[0]: 0x01088468

Nov 26 10:46:21 JRiMac kernel[0]: 0x000004c0

Nov 26 10:46:21 JRiMac kernel[0]: 0x00000000

Nov 26 10:46:21 JRiMac kernel[0]: 0x000100c0

Nov 26 10:46:21 JRiMac kernel[0]: ** GPU Debug Info End **

Nov 26 10:47:34 JRiMac kernel[0]: nstat_lookup_entry failed: 2

Nov 26 10:51:57 localhost kernel[0]: Darwin Kernel Version 11.2.0: Tue Aug  9 20:54:00 PDT 2011; root:xnu-1699.24.8~1/RELEASE_X86_64

2010 27"iMac 16GB

passes all diagnostics

The problem may very well be related to power management. 

In addition to the UI freezing, my iMac runs very hot when using LION.  I don't know the precise temperature, but I have noticed that the top and rear of the machine become very hot within minutes of starting---much hotter than it ever did using LEOPARD.  And I am not doing any kind of intensive processing to justify such high temps.

Also, LION drains my bluetooth keyboard's batteries within 9 or 10 days.  Batteries lasted at least a month using Leopard.