MacOS Sierra not recognizing external displays and going black

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.

I might have found a temporary work around from this site and quoted below: https://www.displaylink.org/forum/showthread.php?t=65562&highlight=high+sierra

Yes the mirror issue is still there. The only way to mirror currently is having a Mac with discrete graphics and making sure the discrete graphics is active (opening Photos for example).

We have to continue pushing for this to be resolved by Apple.

I don't know what "discrete graphics" are, but I opened Photos as was suggested, and while my MacBook Pro screen still goes black, I am able to see it on the TV now.

I might have found a fix...at least a temporary work around. I found this on a DisplayLink forum:

Yes the mirror issue is still there. The only way to mirror currently is having a Mac with discrete graphics and making sure the discrete graphics is active (opening Photos for example).

We have to continue pushing for this to be resolved by Apple.

I don't know what discrete graphics are, but opening Photos before I plugged in my Targus 110 seemed to work for me. My MacBook screen goes black, but I can see it on my TV.

Thanks for sharing this! I have a Late-2012 iMac. My 2nd external monitor went black quite a while back (even tho it showed in the monitor "arrangements" window. This fix brought it to life again! Much appreciated.

TmacKilla's link and Instructions:

http://www.nvidia.com/object/macosx-cuda-8.0.46-driver.html

This little driver made my 2012 Mac Pro Retina with 660 GTX actually fly and run way more efficient graphic wise and fixed my external monitor hiccups.

you can update via system prefs.

I had the same problem but was able to fix it by reinstalling the latest update to DisplayLink that is more compatible with the new IOS. Hope this helps.

http://www.displaylink.com/downloads/macos

HDMI to my LG TV failed after High Sierra upgrade.

Installed that DisplayLink driver above. Bingo! All sorted.

Cheers tiffyzsmile 🙂

Just bought a new MacBook Pro 15'' Retina, OS Sierra V. 10.12.

Tried a bunch of online solutions to make my Samsung external monitor to work and nothing solved.

I'm using a HDMI/Thunderbolt Cable into an apple adapter to Thunderbolt/USB-C.

gianberselli wrote:

Just bought a new MacBook Pro 15'' Retina, OS Sierra V. 10.12.

Tried a bunch of online solutions to make my Samsung external monitor to work and nothing solved.

I'm using a HDMI/Thunderbolt Cable into an apple adapter to Thunderbolt/USB-C.

I believe you may be using the wrong mixture of cables.

Please clarify: are you using a Thunderbolt 3-to-Thunderbolt 2 adapter, and then a cable with Thunderbolt connector on one end and HDMI at the other? Or is it a miniDP-HDMI cable? miniDP has the same plugs as TB2, but they're not the same thing; the TB3-TB2 adapter does NOT carry the miniDP signal.

You should be using a USB C-HDMI cable or adapter, or a USB C dock with HDMI.

Hi. I've been using a LG proyector (AN 110B) with my Mac mini for years through an HDMI connection. Now stopped working. I can connect the Mac to another proyector and the proyector is working with other devices, but when I put them together, "No signal" message appear... I'm struggling with it within the last days... chating with LG and Apple service without any result... they blame the other... I can use the thunderbolt-HDMI to work with the Mac mini in my SONY TV, so I can try things... nothing is working so far...

I'm desperate...

Any help?

I have the same issue on my late 2013 Macbook Pro with MacOs High Sierra. Neither my HDMI port works nor my external display through thunderbolt. My old 27" thunderbolt Mac Screen does though. This bad... :-/

HI,

I have MacBook Pro Retina Retina Mid 2012 (High Sierra 10.13) and I have problem connecting it to my SONY projector via a HDMI cable. I tried SMC reset but it is not working. The screen will just not detect any output. I tried it with my SAMSUNG TV with a different HDMI cable and it still doesn't work. Anyone having the same problem or found a solution?

Nope. I tried that, restarting my mac. The sound works through the hdmi cable, so I am sure there is nothing wrong with the projector and cable. The projector just stay on the default blue screen, don't even have the option to select a hdmi option. Has anyone try downgrading back to El Capitan?

I checked the Nvidia website for mac drivers for sierra. LOW AND BEHOLD! THEY EXIST!

http://www.nvidia.com/object/macosx-cuda-8.0.46-driver.html

This little driver made my 2012 Mac Pro Retina with 660 GTX actually fly and run way more efficient graphic wise and fixed my external monitor hiccups.

you can update via system prefs.

Didn't feel the need to search for drivers until I installed MAC OS SIERRA.

EVEN THOUGH I LOVE APPLE! GREAT PRODUCTS! SHAME ON APPLE FOR GIMPING THE GRAPHICS DRIVER IN AN ATTEMPT TO FORCE UPGRADE!!

I bought an HDMI cable, going through a HDMI>USC C adapter and it is working fine.

gianberselli wrote:

I bought an HDMI cable, going through a HDMI>USC C adapter and it is working fine.

I am glad you got it working.