agpastore

Q: MacOS Sierra not recognizing external displays and going black

Hi.

I've just upgraded to macOS Sierra on my MacBook Pro Retina Mid 2012.

After the upgrade, my Mac is not recognizing any external display:

I've tried HDMI and DisplayPort to VGA adapters.

 

The Retina monitor "blinks" but not signal is detected on external displays.

Also, after rebooting, also the retina monitor goes completely black (the mac has booted, because I can trigger Siri commands!).

 

To restore the situation I need to put the mac to sleep, plug in an hdmi monitor (which does nothing), wake up the mac and eject the plug. After this sequence the retina monitor goes back on (and only that!).

 

I've tried to reset NVRAM and SMC: no effect.

I've tried to boot into safe mode or recovery mode, but the retina monitor remains black, as well as any other external display (the same happens if I try too boot with or without a connected external display).

 

I'm stuck and have no idea on what to do. I cannot even try to reinstall the OS, as no video works just after reboot.

 

Any hint would be appreciated.

Thanks!

MacBook Pro (Retina, Mid 2012), macOS Sierra (10.12)

Posted on Sep 26, 2016 4:31 AM

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Q: MacOS Sierra not recognizing external displays and going black

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  • by mario49,

    mario49 mario49 Sep 27, 2016 11:54 AM in response to agpastore
    Community Specialists
    Sep 27, 2016 11:54 AM in response to agpastore

    Hi agpastore,

    Thank you for using Apple Support Communities. Based on what you stated, it seems like you are having trouble with the MacBook display and an external display both going black. It looks like you have already done some troubleshooting. I would recommend you read this article, it has some more steps that may be able to help troubleshoot the issue:

     

    Get help with video issues on external displays connected to your Mac - Apple Support

     

    Cheers.


     

  • by agpastore,

    agpastore agpastore Sep 27, 2016 12:19 PM in response to mario49
    Level 1 (11 points)
    Notebooks
    Sep 27, 2016 12:19 PM in response to mario49

    Hi mario49,

    thanks for your reply.

     

    However none of the suggestions reported in the article were relevant or effective.

    I had eventually to bring my MacBook at an Apple Store for assistance.

    None of the technicians at the Genius Bar were immediately able to trace the problem,

    which they never saw before.

     

    The could not even boot the Mac over the network using their diagnostic tools...

    (the retina display was totally black - not even the Apple logo on the back side)

     

    Now I'm eagerly waiting for their response...

  • by oleguerilustrum,

    oleguerilustrum oleguerilustrum Sep 28, 2016 1:46 AM in response to mario49
    Level 1 (4 points)
    Sep 28, 2016 1:46 AM in response to mario49

    I have the same problem.

     

    This is the message I get on the Console app when attaching an external display (Dell ST2420L) via a Thunderbolt to HDMI cable (it's for the WindowServer process):

     

    [ERROR] - Driver reported mode info is out of sync with current mode info. Display 4280500, driver's bytePerRow = 10240, driver's width = 3360, stored width = 3360. Forcing rowbytes to be 4*modeInfo->ioModeInfo.nominalwitdh.

     

    The message is repeated several times, and also appears when de-attaching the cable.

  • by summeress,

    summeress summeress Oct 3, 2016 1:08 PM in response to agpastore
    Level 1 (4 points)
    Mac OS X
    Oct 3, 2016 1:08 PM in response to agpastore

    I have the same issue as well.  When attempting to connect with an external projector as a second monitor, the projector does not connect properly and all I see a blue/default screen.  Another issue I noticed is that when I start my computer with the projector connected to the iMac both screen go blank/purpleish black and all I see is a cursor that can be moved around.  However, when I unplug the thunderbolt adapter to the projector, the iMac screen comes back to the login screen.

     

    There is definitely something wrong with macOS Sierra and I would really like to go back to the previous version.

  • by agpastore,

    agpastore agpastore Oct 3, 2016 10:43 PM in response to summeress
    Level 1 (11 points)
    Notebooks
    Oct 3, 2016 10:43 PM in response to summeress

    I left my MacBook one week at a Genius Bar, they asked me about 500€ for replacing the whole motherboard, but I declined the offer, as I think (and hope nonetheless!) it's a software bug, not an hardware issue.

     

    After getting the mac back, now it boots regularly, and when I connect an external display it seems to be recognized and working immediately, but within 15 secs it goes kernel panic'ing with a GPU panic fault and reboots.

     

    My last attempt will be a downgrade to El Capitan...