Jeremy Liu

Q: iMac (Retina 5K, 27-inch, Late 2015) Randomly Restarts Without Errors

My iMac has been randomly restarting itself (about once a day) when it is idle.  Has anyone else experienced the same problem?  I found a YouTube video and it is exactly what happened to my iMac:  https://www.youtube.com/watch?v=ka7lUIeiH5E

 

I witnessed it once -- the computer was on (not sleeping) with the display off, nothing CPU/GPU intensive running.  I suddenly heard a chime and saw that the computer restarted itself.  I logged in.  There was no pop-up window.  I launched Console and did not see anything unusual before the restart.

 

More information:

 

  1. The computer is idle when restart happens.  Nothing on the computer indicates it overheats.  Display is off (due to inactivity) and fan is quiet.
  2. There is no trace of software shutdown, kernel panic or crash.  System log shows normal activities and then a sudden BOOT_TIME entry, as if someone yanks the power cord.
  3. It is not a power failure because the computer should be off if it is really a power failure.  "Start up automatically after a power failure" is not checked.
  4. It started to happen after I came back from a trip and upgraded my iMac to the latest Mac OS X five days ago.  This computer was purchased last October and I had never seen something like this until a few days ago.

 

The comments on the YouTube video suggest a total replacement, but I'm reluctant to do so if it turns out to be a software/firmware problem that can be fixed. -- The computer is heavy and the nearest Apple Store is not very close, not to mention the backup/restore efforts.

 

Thanks

iMac with Retina 5K display, OS X El Capitan (10.11.4), Retina 5K, 27-inch, Late 2015

Posted on Apr 7, 2016 6:45 PM

Close

Q: iMac (Retina 5K, 27-inch, Late 2015) Randomly Restarts Without Errors

  • All replies
  • Helpful answers

first Previous Page 15 of 19 last Next
  • by mrdgvb1,

    mrdgvb1 mrdgvb1 Jul 24, 2016 9:24 PM in response to dj-anon
    Level 1 (16 points)
    Desktops
    Jul 24, 2016 9:24 PM in response to dj-anon

    Apple is going to replace my logic board. Finally. They are actually sending a tech out to my house to do it. I am supposed to get an appointment in the next 48 hours. Will update everyone when logic board is replaced and if the restarts stop - which I am confident from others like you who say the reboots have stopped with this fix. 

     

    I am pleased and hopeful.

  • by vandan,

    vandan vandan Jul 24, 2016 10:30 PM in response to mrdgvb1
    Level 2 (214 points)
    Desktops
    Jul 24, 2016 10:30 PM in response to mrdgvb1

    I have been having this problem very sporadically, maybe once a week or so.  When I go to the console, which log would look at to see if there is a -128 error?

     

    I have no external monitors or devices connected other than a usb hub.

     

    My one year warranty runs out in October so I want to make sure I get this resolved before then.

     

    Thanks!

  • by dj-anon,

    dj-anon dj-anon Jul 25, 2016 5:43 PM in response to vandan
    Level 1 (38 points)
    Safari
    Jul 25, 2016 5:43 PM in response to vandan

    Just use the search box on the upper right corner and type "-128". Should be easy to find immediately after a reboot.

  • by vandan,

    vandan vandan Jul 25, 2016 8:39 PM in response to dj-anon
    Level 2 (214 points)
    Desktops
    Jul 25, 2016 8:39 PM in response to dj-anon

    Thank you.

     

    This is what I get when I do that:

    Screen Shot 2016-07-25 at 8.32.20 PM.png

    It seems like this is saying my computer shutdown at these 7 times throughout the day today.  But, as far as I know this isn't true.  When it reboots the startup login screen comes up with my user name and the other user options.  However, each time I went to use it today it was at the wake up screen where I'm prompted for my password to wake it from sleep.

     

    Hope  this makes sense.

  • by chrisrobinsonSD,

    chrisrobinsonSD chrisrobinsonSD Jul 26, 2016 8:51 AM in response to mrdgvb1
    Level 1 (4 points)
    Jul 26, 2016 8:51 AM in response to mrdgvb1

    Is the the home service part of AppleCare or will they also do this under normal warranty work?

  • by Emptynet,

    Emptynet Emptynet Jul 26, 2016 12:06 PM in response to vandan
    Level 1 (4 points)
    Desktops
    Jul 26, 2016 12:06 PM in response to vandan

    Hi folks

    I dropped my iMac off at the Genius Bar tonight (don't hold out much hope of it demonstrating the problem but hey ho).

    A couple of (possibly) useful snippets of information however:

    The Genius I talked to went to research the shutdown cause of -128 and came back quite forcefully suggesting that *I* must have shut the machine down because that cause related to "an application cancelled shutdown". Now that's clearly nonsense, as the machine did in fact restart, but it does make *some* sense as there was no way to quit the apps before the machine restarted? Take with a large pinch of salt, YMMV etc.

    One other point - the "Previous shutdown cause" message does appear to be generated at multiple times, and doesn't get changed *until* another restart type occurs, e.g. a clean shutdown or a reboot will change it to 5 or 0 (can't remember which way round).

    Cheers

    Mike

  • by mrdgvb1,

    mrdgvb1 mrdgvb1 Jul 26, 2016 3:32 PM in response to Emptynet
    Level 1 (16 points)
    Desktops
    Jul 26, 2016 3:32 PM in response to Emptynet

    Just had my logic board replaced by an In-Home Technician . Yay! This is his fourth logic board replacement on the late 2015 5K Imac... says this should solve the issue as the Logic Board (Mother Board) has everything on it - basically the body of the computer.

     

    Says the three other ones they replaced are running without the random restart issues. I am hopeful that the problem is now resolved. He suggest Apple Care as it includes in home service. Pretty fast too, less than a 48 hour turn around for the appointment and it took him 45 minutes to do the swap.

     

    Just keep on Apple until they okay the Logic Board replacement. You can see from the photo it has the Video Chip, memory slots, USB connections, etc.

     

    Logic Board.jpg

  • by dubiya,

    dubiya dubiya Jul 27, 2016 11:54 AM in response to mrdgvb1
    Level 1 (8 points)
    Desktops
    Jul 27, 2016 11:54 AM in response to mrdgvb1

    I'm squarely in the Apple box of runaround with my problem, sounds the same as yours. I did os x reinstall with apple online, then took it to apple authorized dealer who did it again plus tests, but couldn't figure it out, now it is with apple store for hardware testing - but wait, they want to do another re-install, but not from my backup - but some hardware tests being done. This is unacceptable, it's now going on a few weeks of this back and forth. Apple should just give me a new refurbished unit now, and throw my machine away. Very frustrating. Not a great customer experience.

  • by Emptynet,

    Emptynet Emptynet Jul 27, 2016 11:48 PM in response to Emptynet
    Level 1 (4 points)
    Desktops
    Jul 27, 2016 11:48 PM in response to Emptynet

    Looking in the logs I found one other interesting snippet. My machine was rock solid stable until 10.11.4 was installed, like many reported here. But that Mac OS X update included a firmware change. And the 10.11.5 update that stabilised many or most of the MacBook problems also included a firmware update. I wonder if the firmware changes are at the root of this issue?

     

    From /var/log/install.log, installation of Mac OS X 10.11.4

      Mar 22 21:35:06 Mikes-2015-iMac Installer[93316]: OSXUpdCombo10.11.4 : 1.0.0.0.1.1457768702

      Mar 22 21:35:06 Mikes-2015-iMac Installer[93316]: FirmwareUpdate : 1.0.0.0.1.1457768702

    Installation of Mac OS X 10.11.5

      May 18 20:52:54 Mikes-2015-iMac Installer[16240]: OSXUpdCombo10.11.5 : 1.0.0.0.1.1462426507

      May 18 20:52:54 Mikes-2015-iMac Installer[16240]: FirmwareUpdate : 1.0.0.0.1.1462426507

    Installation of Mac OS X 10.11.6

      Jul 20 20:16:19 Mikes-2015-iMac Installer[12662]: FirmwareUpdate : 1.0.0.0.1.1468031924

      Jul 20 20:16:19 Mikes-2015-iMac Installer[12662]: FullBundleUpdate : 1.0.0.0.1.1468031924

  • by /etc,

    /etc /etc Jul 28, 2016 4:50 AM in response to Emptynet
    Level 1 (4 points)
    Jul 28, 2016 4:50 AM in response to Emptynet

    Emptynet,

    I've been wondering if this is due to a bad firmware update, too.  Replacing the logic board would certainly be one way to get working firmware.  This could explain why the 10.11.4 update broke our systems and why some have found a fix with a new logic board.  If the replacement board came with pre-10.11.4 firmware, then it'll be running firmware that doesn't exhibit this problem.  As long as an update having the 'bad' firmware isn't installed after the logic board was replaced, then the system would continue to run with the firmware that came with the replacement board.  Also, if it's a problem with a firmware update, then it would be much easier to get a firmware update from Apple to fix this than to get Apple to replace all of our logic boards, so that would be good.

     

    So, one question we should try to answer is if those who have had their logic boards replaced are now running a different version of firmware than those of us having this problem.  It would be helpful if someone who has the logic board replacement that fixes this problem would post their firmware version.  This can be found in the main  menu under 'About This Mac', then clicking on the 'System Overview...' button.  Here, there will be a 'Hardware Overview' page with the following two lines:

    Boot ROM Version: IM171.0105.B08

    SMC Version (system): 2.34f2

  • by Michael M,

    Michael M Michael M Jul 28, 2016 6:05 AM in response to /etc
    Level 1 (123 points)
    Wireless
    Jul 28, 2016 6:05 AM in response to /etc

    Logic board replaced first week of June. Came back with 10.11.5 installed. NO restarts in 7 weeks. Hope this helps.

     

    Screen Shot 2016-07-28 at 9.01.35 AM.png

  • by mrdgvb1,

    mrdgvb1 mrdgvb1 Jul 28, 2016 7:26 AM in response to /etc
    Level 1 (16 points)
    Desktops
    Jul 28, 2016 7:26 AM in response to /etc

    Logic Board replacement seems the solution. Tech who did mine says it is bad firmware.

  • by mrdgvb1,

    mrdgvb1 mrdgvb1 Jul 28, 2016 8:07 AM in response to chrisrobinsonSD
    Level 1 (16 points)
    Desktops
    Jul 28, 2016 8:07 AM in response to chrisrobinsonSD

    The Apple supervisor arranged for an in home repair. It is part of Apple Care (which I didn't have) but apple can authorize it for you. You just need to be persistent. In home is easy and great. I will be getting Apple Care also for future protection.

  • by Vannter,

    Vannter Vannter Jul 28, 2016 8:18 AM in response to mrdgvb1
    Level 1 (5 points)
    Desktops
    Jul 28, 2016 8:18 AM in response to mrdgvb1

    My machine is still under warranty and I have Apple Care but it was determined that there were no in-home repair options close enough to me. So I have to pack up my machine and make the hour+ drive to the closest repair center. If I had known that in advance, I wouldn't have paid for Apple Care. Sigh.

  • by mrdgvb1,

    mrdgvb1 mrdgvb1 Jul 28, 2016 9:01 AM in response to Vannter
    Level 1 (16 points)
    Desktops
    Jul 28, 2016 9:01 AM in response to Vannter

    I am fortunate to be in So Cal where there are 3 Apple Stores within 25 minutes of my house plus a bunch of local computer stores working with Apple. But the Tech with 17 years of experience says it is the Firmware for sure.

first Previous Page 15 of 19 last Next