Level 1

41 points

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

Top-ranking reply

lbsanch11

Level 1

4 points

Posted on Nov 11, 2017 2:34 PM

I had the same issue when updating to OS High Sierra. Are you using an "Other than Apple" adapter to connect the monitor to the computer? I am using a j5create usb 3.0 to vga adapter and went to the j5create website and downloaded the software again for this specific adapter. My external monitor immediately worked again after restarting.

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109 replies

Nov 1, 2016 8:12 AM in response to mwg986

mwg986: Where is this update you are referring to? I do not see one that pertains to other aspects of the OS, but not external display bug fixes. My most recent Sierra version is 10.12.1 installed yesterday.

Nov 2, 2016 3:21 PM in response to oleguerilustrum

I have the exactly same problem. Do you have some news about this?

Nov 2, 2016 4:39 PM in response to Gabriel Soares

Can you please at least tell us what is your setup?

What mac/monior model....

Nov 2, 2016 4:43 PM in response to CNcarborough

MacBook Pro (15-inch, Mid 2012)

2.6 GHz Intel Core i7

8 GB 1067 MHz DDR3

Intel HD Graphics 4000 1536 MB

Nov 2, 2016 4:44 PM in response to fender1987

What about monitor? Cable?

Nov 2, 2016 4:51 PM in response to CNcarborough

Using MiniPortDisplay to VGA cable and connecting to an NEC projector. Not sure of the model number at the moment as it is at work. My computer will connect fine to my Vizio SmartTV via the same cable means, which leads me to believe it is an issue with the projector and not Sierra. Today I booted my computer and pressed Command-R to open Utilities and re-installed Sierra. Still got the same result, which was no image on the screen. Opened Displays in System Preferences and hit Option-Detect Displays and still nothing.

Nov 2, 2016 6:13 PM in response to fender1987

Do you have kernel panic report? I posted my report on here

Re: What may have caused the following kernel panic? macOS Sierra, Samsung EVO 850, TRIM enabled.

I also I filed a bug report to Apple here https://bugreport.apple.com

Nov 5, 2016 2:06 PM in response to agpastore

Same problem here.

MacBook Pro (Retina, Mid 2012)
2,3 GHz Intel Core i7

Intel HD Graphics 4000 1536 MB

+ LED Cinema Display 27"

Nov 10, 2016 5:57 PM in response to agpastore

Sounds like I've got something similar:

MacBook Air 11in (Mid 2013)

Acer K222HQL via a MDP > DVI cable

It's been working fine for the past couple years; It just didn't after I did the 10.12.1 update today (I intentionally waited a few weeks to prevent this kind of thing!). I even went ahead and "reinstalled" OSX via recovery mode. Nothing.

Connected a different computer to the display—worked fine.

Connected the computer to my TV—worked fine.

Nov 16, 2016 6:35 AM in response to Jack Weinbender

Aaaand. Now it works again. No clue.

Nov 17, 2016 6:45 AM in response to Jack Weinbender

Restarted, back to nothing.

Nov 17, 2016 9:49 AM in response to agpastore

Same thing. Sometimes its OK, most of it, not OK.

Just got back to El Capitan. So far, 100% working.

The problem for sure is Sierra.

Dec 3, 2016 3:42 PM in response to agpastore

Had a problem with my VGA to USB display after installing Sierra. Didn't recognize it at all.

Solved it by installing the latest DisplayLink driver (3.0 Beta 1) -> http://www.displaylink.com/downloads/osx

Dec 4, 2016 12:08 PM in response to agpastore

It is because Apple doesn't support older monitors anymore. I have a HANNS-G HW191D monitor connected to a Thunderbolt docking station and in El Capitan this setup worked perfectly but after "upgrading" to Sierra the Monitor is not recognised at all. First I thought the docking station or cable was not working but when I rebooted the macbook pro into bootcamp the monitor worked again without any problems.

So then I thought maybe Sierra doesn't support dual monitor on my setup anymore but I could connect my LG TV with the same DP+HDMI cable and the TV was immediately recognised.

This is definitely a change in the new MacOS update that causes older external monitors to break. Shame on Apple.

Dec 5, 2016 4:48 AM in response to agpastore

Sorry to disapoint, but its not the fact that the monitor is old.

I have brand new 34" LG and have the same problem.

Works fine at El Capitan.

Dont work at all with Sierra.

So, the problem is Sierra for sure.

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MacOS Sierra not recognizing external displays and going black