MacOS Sierra not recognizing external displays and going black

Make sure the appropriate input for your tv is selected, then open System Preferences->Displays, hold down the Option keys and press "Detect Displays". Anything?

That doesn't help at all.

MacBook Pro (Retina, Mid 2012) - Sierra - 10.12.3 - Having same problem. Blank retina display on restart. Cannot safe boot or recovery boot. But, can login using teamviewer and can recover via sleep and wake tactics. No clear pattern. No external monitors are detecting. But, when removing connection to monitor (HDMI or Thunderbolt), the LCD screen resets. Still trying to identify patterns that cause this.

I get no console notification when plugging in monitor. But, when I disconnect monitor (HDMI or Thunderbolt), I get the following:

[ERROR] - Driver reported mode info is out of sync with current mode info. Display 42803c0, driver's bytePerRow = 11776, driver's width = 3360, stored width = 3360. Forcing rowbytes to be 4*modeInfo->ioModeInfo.nominalwitdh.

Biggest concern is lack of visible Apple at startup - and no ability to get into recovery mode. These are critical problems I can't address. I have reset VPRAM and other suggested procedures. Nothing has worked.

Just wanted to give you guys an update. It seems to be fine after I updated my Macbook Pro to the latest Mac OS Sirrea 10.12.2. No more black screen at start up or reboot.

Macbook Pro 15 (Mid 2014 with NVIDIA GeForce GT 750M)

Samsung 4k (U28D590) Display

Mini/thunderbolt display port cable.

I recently had my hard drive replaced (for a recall), I was on Sierra before and my external display had no issues. After I got my hard drive replacement I am experiencing the same issue. This is 100% software related, nothing to do with age of the display either. I've searched several different forums for an answer and spent far longer than I should have. I've really enjoyed Apple's operating systems over the last several years but this is probably my last straw with them. Known issue for several months and no feedback anywhere from Apple. For some people being limited to only one display greatly limits productivity.

I have the same issue and I have updated to Version 10.12.2. I'll have to try the DisplayLink driver (3.0 beta 2 - 23 Dec 2016) but so far what worked was unplugging my adapter for my external monitor AND also my ethernet to USB adapter and the Mac will start showing the Apple logo with the progress bar. (Don't need to force shut down and press power again).

Had a user with this same issue. Seems an aftermarket dongle will not work. You have to go out and buy the OEM Mini DVI adapter made by Apple specifically for it to work. Is this a software issue I doubt it. It seems that Apple made it this way by maybe embedding something in there dongle that only works for there laptop. When going from the Mini to the dongle using a digital signal and then to an analog signal such as VGA this is when the case is present. Not sure it this issue is present when going digital to digital. Regardless, did Apple force people to buy there product and not allow for the use of aftermarket content. Also, tried it with aftermarket dongle that is manufactured after sierra came out and it does not work. Tricky or Shady? Which one?

So here's my issue. I had an aftermarket Monoprice MiniDisplay to VGA dongle that worked fine with my Mid-2012 MacBook Pro 15" on OSX, El Capitan, and Yosemite and an NEC projector. I then downloaded Sierra 10.12.1 and the dongle no longer worked! Tried with a different, newer aftermarket MiniDisplay to VGA and still nothing. My MacBook Pro 13" running El Capitan was able to connect with the new, but not the old Monoprice. The only way I could get either dongle to connect with the MacBook running Sierra was if I shut the computer down, connected to the projector, and booted the machine. The dongle would then allow the laptop to connect to the projector. Once I disconnected the dongle while the computer was on and tried to reconnect, it would no longer detect the projector. I sometimes use this dongle to connect to my 60" Vizio SmartTV via the VGA port on the TV. It sends the signal fine and I am able to connect, even though I have Sierra installed. Went through all the steps listed in this forum. Reset the NVRAM, reset the PRAM, reset the SMC, went through all the garbage in the "Display" tab in System Preferences, clicked Option while in Displays and selected Detect Displays, updated to Sierra 10.12.2, downloaded and installed DisplayLink Driver, tried to run Mini DP VGA Update (did not recognize any display to update), booted machine in Recovery mode and did a Re-Install of Sierra 10.12.2. Finally, I bit the bullet and spent the $30 on an Apple brand MiniDisplay to VGA adapter and, drumroll please.... It worked! So what have we learned here? There has to be something in Sierra that is recognizing I am not using an "Apple approved" or "Apple brand" adapter. The Monoprice is passive and not bi-directional, not sure about the other aftermarket one I have. But both worked on earlier OS's. I know the Apple MiniDisplay to VGA is active, is it also bi-directional? Is this perhaps the reason it works? Since it is bi-directional, it is allowing the projector to communicate back to the laptop? It will be interesting to see how all this plays out. I am hanging on to the aftermarket adapters and will try them after future updates. I know Sierra 10.12.3 beta is out for Developers, so we'll see what comes next.

I'm using club3d DVI-HDMI adapter with my Sony X800D TV. The adapter was working just fine with El Capitan. I just updated to Sierra (What a bad decision) and now it stopped working. All I can see is black screen with pink bar at the top on my TV. Club3D is also passive, so I'm not sure why Sierra doesn't like it. What a bummer.

I have the same problem now. I've been using a MacBook Air (Mid 2013 Haswell model) connected to a 34" Ultra-wide monitor at 3440x1440 resolution. I know this MacBook air can't run this res at 60hz, so I've been running at 30hz until I can upgrade my laptop. It worked fine until I installed 10.12.3 this morning, and now nothing! I connect in using Belkin mini-dp to dp cable. When I connect in the display, the MacBook display blinks for a second, then stays on and the display never connects. I noticed the release notes say it "improves MacBook Pro graphics switching." Well I'm wondering if that's screwed me up though!

I don't think it has to do with monitor. I have Macbook Pro 15" (2015) and using Club3d DVI-HDMI adapter to output 4k@60Hz to my Sony X800D TV. It's fairly new model (Sony released it last year) and working just fine with El Capitan. This morning, I updated to Sierra and the adapter couldn't output 4k@60Hz anymore. My TV just shows black screen with pink line at the top. So many people are having the same issue with external TV and I have no idea how to fix this issue. Now, i'm trying to remove Sierra and reinstall El Captian.

After upgrading, my external display only works if I unplug it before booting up. After the desktop appears, I plug it back in and it works properly. This is quite annoying since my MacBook display is shattered and I cannot see the sign-on screen. I finally figured out that I could blindly type the first letter of my User Name, followed by the return key, followed by my password to login.

I figured something out for this issue. I've been using a Henge Dock for my Macbook Air so I have to close the lid and connect it to power to dock it (and the external display doesn't work under Siera). The other day I tried hooking up the display while the MacBook was open and running and it worked! I could subsequently close the lid and the external display still worked. So for some reason, Siera won't let me hook up an external display with the MacBook lid closed. FYI APPLE - Fix it please!

Sometimes the cause is as silly as leaving caps-lock on when typing a password.

In this case, many monitors have multiple input ports, HDMI1, HDMI2, HDMI3, VGA1, VGA2 etc. If your monitor is not programmed to use the signal from the same port as the input cable, your screen will stay black.

Also, assuming you are not in the middle of a power-cut or anything like that, you should look to see if the monitor power cable is plugged in correctly.

Lastly, you should rule out a problem with your monitor by making sure it actually works with a different laptop.

I am pretty sure it's a Sierra bug, especially for hdmi adapter.

My latest MacBookPro USB-C to hdmi or legacy MacBookPro/Mac mini's Thunderbolt2 to hdmi are all having this issue.

As long as the MacOS went to sleep, and the to-hdmi adapter port off(e.g: monitor power off)/unplug, next time the port becomes on/plugged. Sierra detected the hdmi monitor but won't display anything(no signal/black).

Then you have to restart Sierra to make it work again.

Note: I tested at least 3 adapters and 1 OWC thunderbolt2 dock with 4 monitors/tv. They result same issues and we're working well before Sierra. It definitely is a Sierra bug, and not been resolved yet(10.13.3)