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

Man, I just realized that my computer is working really hard when I get these freezes.  I noticed before that the fan was really active when I was having a spazz attack.  Sometimes switching to a different program helps clear the problem.  When I did that before, as soon as the problem cleared, the fan stopped working so hard.  Am I overheating?  Somehow overworking the system?

Also, I notice lately I've been getting a lot of script errors in Firefox that I think have to do with the Facebook chat.  Probably a symptom of the system getting stuck rather than a cause.

I think I'm going to start emailing Apple every time an instance occurs, or at least once a day.  This problem has become so overwhelmingly unbearable that I think they should have to suffer as much as I am.

I decided today to do an experiment to try and eliminate the causes of this video problem.  I had a hunch on it and I think I might be right.  I'm going to post the entirety of my notes here.

1)  First I closed everything except iTunes, my TextEdit app, and the Twitter App which was running in the background.  Everything else was closed, ESPECIALLY all browsers.

I began watching Harry Potter in iTunes (purchased from the iTunes Store) for an hour and a half.  During this time I moved my mouse around, including over the dock which often sticks and freezes and causes the mouse to jump around.  I maximized, minimized, and viewed the video in Full Screen.

About 45 minutes into the movie I opened Thunderbird, which is regularly checking mail in the background every five minutes.  I had this minimized and running in the background.

About an hour in I closed TextEdit.  I also opened and closed the Twitter app, scrolled through, updated, gave it a good workout.  Sometimes the mouse gets wonky when running across the Twitter app itself… this did not happen and the video continued playing normally through the end.

2)  Once I ascertained that the movie played acceptably, I decided to view some other movie files in VLC player.  I played with the size, volume, and again had Thunderbird and Twitter open.  No issues.

3)  THEN I opened Safari, which restored a previous session with four tabs open.  With the browser open, I ran Harry Potter again in iTunes, which played fine.  I then paused HP and went back to Safari and watched a video on YouTube. It played fine for several minutes.  I then viewed it in FullScreen mode and shortly after it started skipping.  I reduced the size back to standard and the video continued skipping.  I closed the tab with YouTube and went back to iTunes where I resumed Harry Potter, which played fine.

4)  Finally, I opened Firefox with a clean session.   I played Harry Potter in the background while using FF.  I went to Wikipedia and there was no change.  I opened Facebook, with the sidebar/chat OFFLINE - video continued fine.  I then enabled chat and left the video running.  I opened a new tab and viewed a forum for a little while.  I then closed the tab.  The only tab left open was Facebook with the chat open (though no chats came through).  The online users list continued to update as did the news feed.  I paused the movie and left Facebook open on top for about 2 hours without using it.

I returned, refreshed my Facebook page, and then switched over to iTunes.  I hit play and the video INSTANTLY skipped.  I tried pausing and unpausing the movie but that didn't help.  I closed Firefox and unpaused the movie.  It continued to skip and I paused and unpaused it several more times, hoping that it would catch itself up.  Finally the movie continued to play normally.  Note that I've noticed a particular lag with Firefox in particular when closing.  It doesn't seem to want to fully close out of the system immediately and lingers a bit.  Twitter is open and still no issues.

My theory was that the problem is coming from a combination of the open browser and the video playing.  It appears that the only time I really have this issue is when I have my browser open, and it's not just limited to one browser.  I've also had the video issue in Chrome.  So I've established a problem linked to both Firefox and Safari and, from past experience, Chrome. 

Would anyone care to experiment with the video skipping/freezing issue in conjunction with an open vs. closed browser?  Or can anyone share based on past experience if the freezing issue occurs only when a browser is open, or recently closed?

Also, could anyone suggest a possible reason for this connection?  Is it possible that the browsers are being allocated too much memory to run the videos with them?  Are they hogging the system?  Any other ideas?

Incidentally, Firefox initiated a system shutdown earlier today.  I saved the crash report before sending it to Apple.  It's what gave me the idea that perhaps the browser is the culprit and not the video itself.

Well I have done all sort of things in order to fix the freezing problem...

From clean Lion install to all the tweeks available...

iMac mid 2011 27in AMD Radeon 6770M

and I even uninstalled the chrome... somebody told me that could be an issue... well let's see...

I think we should create a FB group about this issue since a lot of people is still having problems with it...

Yes totally wait...

I did a clean Lion install (i have been following this thread too since day 1) and the problem still there...

@joeygillis  I have been coming to the conclusion that an open browser is the root--or at least part of the root--of the problem. I use just Safari. I've noticed that each and every one of my freezes/crashes occur soon after bringing my mac out of sleep and when I am using Safari for a few minutes. I am going to further try to test this by seeing if I experience a crash/freeze by not using Safari

I have a similar issue.  My iMac started freezing up suddenly, mouse cursor still work, but the computer is unresponsisve to mouse clicks or keyboard.   I erased the hard disk, and am trying to reinstall Lion from scratch.  The first step of clean install seems to work fine. It copies everything from usb flash drive to imac hard disk OK.  I have done this at least 4 times, and it works OK.  The 2nd step is restart and config of Lion.  After restart, it asks about keyboard type and registration info, then freezes up.    I restarted a few times and tried to complete the lion install, but it freezes up at different points in the startup install sequence.

edited

Message was edited by: User_101011

I tried changing the display resolution. I thought it had helped, but the morning crash still arrived NVIDIA errors, then screen freeze as usual.

An apple support person said it might be a RAM problem - but I've run memtest continuously for about 48 hours and it didn't find any errors at all - in single user mode as well..

Mid '10 27'' iMac, I had the same problems both on Windows and after installing Lion. Before Lion with various driver tweaks on windows I had eliminated most of it, but on Lion it returned.

SMCfanControl DOES WORK.

Of course it's not the optimal solution and I still get a few artifacts after my fans are in full speed and it makes it sound like a car factory, but for a solution till an actual solution comes it's something.

There seems to be an issue with Lion after sleep mode - that may affect all Radeon GPUs 6770M, 6870 and 6970M.

On my system graphics performance is up to 3x slower after sleep mode!

Here are my Unigine benchmark results that show the issue:

LINK: Unigine 3.0, MacPro 3,1, Lion 10.7.3, Radeon HD 6870 - BEFORE sleep mode (score 1302)

LINK: Unigine 3.0, MacPro 3,1, Lion 10.7.3, Radeon HD 6870 - AFTER sleep mode (score 441)

To solve the issue I either need to reboot or switch screen resolution from 1920x1080@60Hz to 1024x768@75Hz and back.

Man in the last few days I've been having some MAJOR issues.  I'm experiencing the sae problems but well beyond having to do with video or anything.  My system is now freezing at will.  I thought it might have had to do with iTunes syncing my iPhone, but even after I unplugged it I still had problems.  My mouse runs all over the screen, or else won't move for a few minutes, I can't Command+Tab through programs, can't type or else letters just stick and repeat, and the other day I had TWO system shutdowns in one day.

I used the Lion restore partition and verified and repaired all my permissions and the disks and still have issues.  I decided to try and let my system cool over overnight, so I put it to sleep which I usually dont' do.  Today I had very few problems.  I wonder if it's overheating?  Is lion making it run too hot?  It's now starting to deteriorate to a point where I won't be able to use it at all.

But even if I have to replace it, what is the option?  Does Apple think I'm going to buy another Apple computer???  The new systems arrive with these issues, and Apple doesn't want to address it, so what am I supposed to do?  I'd hate to go back to a Windows machine but at least it'd be cheaper.

I've been suffering this problem for some time now. I just did a clean install of Lion last weekend and that was an experience. I created a Lion boot DVD and at one point the computer reboots to complete the install. My computer hung up at that point and I was stuck for a bit and unable to reboot and get back to the initial DVD install menu. After searching google I found that someone else had a similar problem and they had to clear the NVRAM first then start the clean install. This worked for me and I completed the install. The next step for me was to enable FileVault which took ~14hrs and failed due to an error. I was then unable to revert back due to another error. More google searching and I was able to use the disk utility to erase the encrypted partition and start all over. My lated clean install skipped the FileVault feature although I still need the encryption but that can wait for another day. When it can time to restore from my time machine backup, Lion did not recognize the drive which ment that the migration assistant was of no use. I was able to manually retore files from the time machine app but this took some time. This took several days to complete!

So now I have my clean install of Lion and the computer continues to freeze often enough that I can't use it for business which is the primary purpose of the machine.

If I fall back to Snow Leopard will this solve my problem?

@TWKP Re Falling back to Snow leopard . . . I've been watching these threads for a while. I have been sufffering from random freezes/crashes, mostly a minute or two after coming out of sleep, but also  with videos and at random. I would strongly suggest that if you do go back to Snow Leopard, you go back to version 10.6.5, before ever going on (if ever) to 10.6.6 or 7 or 8.I had no problems with 10.6.5, then a few freezes/crashes with 10.6.6 and more with 10.6.7 and 8. I now have 10.6.8 and am contemplating going back to 10.6.5.  From what I have read on these discussions, it is easier to go back to Snow Leopard if LION was not factory installed on your mac. Will it solve your problems?? Read on in these discussions, BUT note that those who have gone back, have gone back to 10.6.8. I have read that others swear that they had no problems with earlier versions of Snow Leopard like 10.6.5. Also, some have pointed out that there were no problems with any of the Leopard series as well. I refuse to go on to LION figuring that I will make my own situation worse.

I am going to revert to Snow Leopard. I can't afford another week of these disruptions. I purchased my iMac 27" computer with Leopard which I believe was 10.5.2 then I upgraded to snow leopard and then Lion. I've been suffering for some time and I can't recall when the freezing started but it most definitly was progressed to the point where the machine is not usable for by business. FYI, I never use sleep mode because I have applications that need to be on or shutdown. So my problem has nothing to do with sleep mode.

I'll follow the suggestion of reverting back to 10.6.5 and see if I can stabilize the environment. FileVault worked for me on Snow Leopard so I'll be able to encrypt my data again. If anybody has any advice, I'd welcome the feedback.

Thanks

Updated info regarding my iMac freezing up:

I gave up on looking for a OS install fix, and took in to Apple for repair.  Apple techs ran some diagnostic software on it, and told me that my main logic board is bad.  They tell me that the freezes are a hardware issue.  The Memory test passed, as wells as other ASD tests.  The machine still freezes up, even while running the special apple diagnostic software.  Since I am out of warranty / apple care on my 2008 iMac, this will cost me $515.14 to have the main logic board replaced.

Instead of pouring in more money in to an older generation iMac, i justed ordered a refurb iMac to get up and running again.