7 Replies Latest reply: Feb 13, 2014 7:20 AM by Jsh1971
Jsh1971 Level 1 Level 1 (0 points)

The last several months my 27" iMac has been freezing at random times.  I can't reproduce the freeze on my own and it only occurs maybe once or twice a day.  When it does freeze the mouse can still move the pointer around but everything is unresponsive otherwise necessitating a hard reboot.

 

I actually rolled back to Snow Leopard at one point thinking it was an issue attributed to Lion, but still had the problem.

 

I will most likely have to take this into the Apple store but thought I'd see if anyone else has experienced the issue before I made that long trip...


iMac, Mac OS X (10.7.3)
  • 1. Re: Late 2009 27" iMac - Random freezes
    TeenTitan Level 4 Level 4 (2,410 points)

    Do you have any thing attached to the computer besides the keyboard and mouse? if so, have you tried disconnecting those extra items from the computer? if so, do you still have the items when those decies are disconnected?

    Have you checked to make sure your software is up todate? (apple menu, software udpate)

    Have you ran disk utility to verify the disk? dose it check out with no erros?

    What is the smart status of the built in drive in disk utility?

    Have you tried runng apple hardware test? Do you get an error message? if so, what error message?

    when the computer freezes, can you use the sound up or sound down on the keyboard? if so dose it respound?

    What about trying to force quit an application when the computer 'freezes

    Have you tried a safeboot?

    Have you tried a SMC reset? have you tried a NVRAM Reset?

    If you disable sleep, do you still have the issue?

    Has the computer been ugpraded in any way?

    What are you doing when the comptuer freezes? what applications are open? Dose it matter what applications you have open?

  • 2. Re: Late 2009 27" iMac - Random freezes
    Jsh1971 Level 1 Level 1 (0 points)

    Answering your questions inline (in red) below:

     

    Do you have any thing attached to the computer besides the keyboard and mouse? Yes.  A USB hub with several external data drives, one being the TimeMachine backup device.  if so, have you tried disconnecting those extra items from the computer? No I haven't.  These devices have been connected for a very long time, well before this issue surfaced.  I will try this later though.  if so, do you still have the items when those decies are disconnected?

    Have you checked to make sure your software is up todate? (apple menu, software udpate) All software is up to date.

    Have you ran disk utility to verify the disk? dose it check out with no erros? Yes - no errors.

    What is the smart status of the built in drive in disk utility?  I'm not sure how to check this.  I'll look into it.

    Have you tried runng apple hardware test? Do you get an error message? if so, what error message?  Yes with no errors. 

    when the computer freezes, can you use the sound up or sound down on the keyboard? if so dose it respound?  Sound up or sound down on the keyboard does nothing.  The only response I seem to get is being able to move the cursor around the screen with the mouse.

    What about trying to force quit an application when the computer 'freezes' No response, see question above.

    Have you tried a safeboot? No, I haven't.  Problem is so intermittent, I'm not sure this would help.

    Have you tried a SMC reset? have you tried a NVRAM Reset? No, I'll try this later.

    If you disable sleep, do you still have the issue? No, I'll try this later.

    Has the computer been ugpraded in any way? Yes, I upgraded to 16GB of RAM.  I actually thought the failures were occuring because of the upgrade, this is what prompted me to run the Apple hardware test.  The test (including RAM) checked out with no failures.  I then removed the RAM and replaced the OEM RAM.  The freezes continued.

    What are you doing when the comptuer freezes? what applications are open? Dose it matter what applications you have open?  The last freeze occured within 2 minutes of waking the computer from sleep.  VMware Fusion was running and that was it.  But the system freezes regardless of what applications are open.

     

    Thanks for your response.  Seems I have a few more things to check.

  • 3. Re: Late 2009 27" iMac - Random freezes
    TeenTitan Level 4 Level 4 (2,410 points)

    Jsh1971 wrote:

    What is the smart status of the built in drive in disk utility?  I'm not sure how to check this.  I'll look into it.

    If a drive has a failing smart status; the text of the drive would be red in disk utilty. But not all hard drives support SMART status.

    Jsh1971 wrote:

    Do you have any thing attached to the computer besides the keyboard and mouse? Yes.  A USB hub with several external data drives, one being the TimeMachine backup device. 

    A failing external drive could cause cause all the symptoms your describing.

    Jsh1971 wrote:

    The last freeze occured within 2 minutes of waking the computer from sleep.

    A failing drive might act up after sleep. Considering this is when the disk has to spin up, start to read data off of the hard drive.

     

    Try using the computer without the external hard drives & USB hub. If the issue stops; then you know it has some thing to do with one of the external hard drives.

  • 4. Re: Late 2009 27" iMac - Random freezes
    Jsh1971 Level 1 Level 1 (0 points)

     

    If a drive has a failing smart status; the text of the drive would be red in disk utilty. But not all hard drives support SMART status.

    SMART status appears to be fine on the drive.

     

    A failing drive might act up after sleep. Considering this is when the disk has to spin up, start to read data off of the hard drive.

     

    Try using the computer without the external hard drives & USB hub. If the issue stops; then you know it has some thing to do with one of the external hard drives.

    I took your advice and removed the USB drives.  Oh, I also tried the SMC reset and NVRAM reset. Also, did a clean install of OS X Lion.  Thought it had finally solved the issue - made it through a whole day with no lock up.  Unfortunately, sometime last night it froze again.

  • 5. Re: Late 2009 27" iMac - Random freezes
    Jsh1971 Level 1 Level 1 (0 points)

    As an update...

     

    Symptoms: Random lockups: 1-4 times per day with seemingly no rhyme or reason.  Usually, the mouse pointer continues to move but the GUI is unresponsive.  Sometimes, when idle, the screen will refuse to turn back on.  In all cases, requires a hard reboot.  Quite a few times, will wake from idle and will freeze about 15 seconds after being responsive.

     

    I've tried to isolate the problem many different ways but symptoms continued.

    - Restored OEM RAM

    - Rolled back to Snow Leopard

    - Clean install of Lion

    - Reset SRAM & PRAM

    - Removed all USB devices, leaving only mouse and keyboard.

     

    Over the last several weeks, taken it to the Apple Store twice.  They run "stress tests" and cannot duplicate the issue.  Thinking I was doing the right thing, I clean installed Lion - didn't want my personal data floating around in the event the computer got shipped out.  Techs said I needed to bring it back without wiping it so they could investigate logs.

     

    Logs prior to lockups pretty consistently show:

    4/17/12 4:40:31.000 PMkernel** Device in slot: SLOT--1 **
    4/17/12 4:40:31.000 PMkernel** GPU Debug Info Start **
    4/17/12 4:40:31.000 PMkernel0x0000944a

    Then a whole lot of hex code, maybe some sort of mem dump.

     

    Took it a third time to the Apple Store last week.  Again, they could not duplicate the issue.  They tried to say it was Vmware Fusion causing the issue, but the lockups occurred prior to installing Vmware.  They replaced both the logic board and video card.

     

    Within 30 minutes of booting up after bringing it home, locked up again.  I then formatted the hard drive, reinstalled Lion.  Ran for about a day with no lockups.  The following day I installed iLife applications and all of the Apple software updates that were in the queue.  Lock ups began occurring again.

     

    So now I'm doing ANOTHER clean install of Lion.  I'm going to install Apple software updates individually with a 24 hour period of no lockups before I proceed to the next.  One of these days, I'll figure out what's causing it.  Maybe.

  • 6. Re: Late 2009 27" iMac - Random freezes
    MCS2010 Level 1 Level 1 (0 points)

    Curious if your lockup got resolved or not as I am having the exact same issues. Mine is also a late 2009 27" and I am about ready to trash it and get a new model. I had to pay a tech to fix it only a couple mos. back with the same problem. The issue then was deemed bad RAM which had to be removed. Now the problem is back again. For all that is  bad about PCs, I never had this problem.

  • 7. Re: Late 2009 27" iMac - Random freezes
    Jsh1971 Level 1 Level 1 (0 points)

    I actually removed the RAM, one board at a time, to see if any was causing the issue.  I did find that one of the RAM boards that seemed to be causing the lock ups, so I removed it and haven't had any issues since.

     

    It was strange, because the RAM even passed tests that I performed, but, anyway it resolved the issue.

     

    Jim