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

Dec 5, 2016 5:15 AM in response to Gabriel Soares

What LG model do you have? I am looking for a 34" myself. ;)

Dec 5, 2016 5:25 AM in response to agpastore

I have this one: http://www.lg.com/uk/monitors/lg-34UM68

Excellent for business, games, movies, everything!

No regrets!

Dec 5, 2016 6:21 AM in response to Gabriel Soares

Thanks. Now I am disappointed as I wanted to get the LG34UM88. :(

agpastore Author

Level 1

41 points

Dec 13, 2016 12:12 PM in response to agpastore

It works! Latest update to Sierra (10.12.2) seems to have fixed everything.

My external monitors are back!

I knew it was not a hardware fault!

And what about those Apple guys at the Genius Bar who asked me 600€ to fix a nonexisting hardware failure??

I think I'll spend some time to pop in at the Apple Store and leave some "customer suggestions"...

Very well then.

I think I'll reconsider upgrading to a newer MacBook Pro after a Kaby Lake release.

Dec 15, 2016 10:01 AM in response to agpastore

I've still got nothing, even after 10.12.2 update.

Dec 16, 2016 12:38 PM in response to Robert Engstrom

Installed 10.12.2 update and my old monitor is still not recognised.

I bought the LG34UM88 and plugged it in and everything works without issues. The monitor is huge though.

Jan 8, 2017 7:35 PM in response to agpastore

I too am seeing the same thing. Any update on this??

jujubai

Level 1

4 points

Jan 8, 2017 10:52 PM in response to agpastore

I'm having the same issue even after upgrading to 10.12.2.

MacBook Pro (Retina, 15-inch)

Dell E2314H ‑ 23" LED Monitor

Mini DisplayPort to VGA Adapter

Jan 30, 2017 2:08 PM in response to tiffyzsmile

This fixed my problem. Thank you tiffyzsmile. Older Displaylink driver does not work with Sierra.

Saga O.

Level 1

4 points

Jan 31, 2017 12:50 AM in response to agpastore

Using the the display's HDMI/DVI port to connect fixed the issue.

jujubai

Level 1

4 points

Feb 8, 2017 10:18 AM in response to agpastore

I switched to an Apple adapter instead of a 3rd party and my display works again. That is the only thing changed.

Feb 16, 2017 10:07 PM in response to moedev

Did reverting to El Capitan fix it?

Edey1029

Level 1

16 points

Mar 6, 2017 7:54 PM in response to agpastore

Sierra no longer supports non-generic display adapter (HDMI, DVI, VGA. ect)

Edey1029

Level 1

16 points

Mar 6, 2017 7:55 PM in response to moedev

Only generic (Apple) adapters work with Mac OS Sierra

xeorex

Level 1

4 points

Jun 28, 2017 6:12 AM in response to Ghost_Russia

I tried this solution but without success

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MacOS Sierra not recognizing external displays and going black