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I have a workplace setup for my Macbook Pro 15" (2011) that is actually two workplaces. One is the Macbook itself, for sitting. The second, right next to it, is a standing desk with an external monitor, keyboard, and mouse.

This works great - I can work on the standing desk, and when my legs get tired, sit down for a while and continue seamlessly on the Macbook.

The only painful point in the transition is that I have to physically disconnect the external display (an Acer 23" display connected through a MiniDP-to-HDMI cable) when sitting down, so the Macbook display becomes the main (and only) desktop again.

Given that I may do this several times a day, this is bound to wear out the connector over time, something I'd like to avoid.

Is there a more sustainable (software-only?) way to disconnect / deactivate an external display?

All I can find on the Google is about the other way round (turning off the internal Macbook display).

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  • i'm having the same pain, everytime i want to play game, i have to unplug the HDMI of the monitor, while keeping keyboard and mouse with the hub,
    – vanduc1102
    Commented Feb 27, 2021 at 10:12
  • Having the same pain.. I have my Macbook and PC connected to the same monitor, and my USB-c connector for Mac also charges it. So when I want to multi-task with my PC I either have to unplug my Mac and stop charging it, or leave it on and move all my opened windows to its local monitor so that I don't miss messages/emails..
    – Yue Y
    Commented Mar 12, 2022 at 3:56
  • One way to mitigate problem is to use HDMI extension cable or HDMI switch. It's easier to switch off that way without worrying about socket wear.
    – Antti Rytsölä
    Commented Oct 8, 2023 at 11:33

5 Answers 5

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+25

There are two solutions I can think of:

SwitchResX has a number of features including "disable display" which should deactivate it until the software turns it back on. From their FAQ:

SwitchResX includes a function to remove a display from the System's list of managed display. This means the display in question, once deactivated, will not be visible from the System or from any application. Only SwitchResX will be able to activate the display again.

Another simple solution is to use a power plug with a remote switch. It's an easy, non-invasive solution that will get the job done without having to install software or have daemons running that could interfere with your display. macOS will not detect the display if the power is cut (though it will if it's in "standby" or "sleep")

enter image description here

Both solutions cost about the same (less than $20USD). SwtichResX has a 10 day free trial and the power adapter comes with a 30 day return. The software has the benefit of being elegant; but the switch, though a bit crude, has the advantage of you knowing for sure you display is disabled because it's physically off.

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  • 2
    I can't remember Windows OS without "Show Desktop only on X" ( i.imgur.com/cngoYoE.png ) in Display Settings. It's been with us forever. Why do I have to install external software (or even hardware!) for such a simple task? Unfortunately I'm not willing to use physical switches and SwitchResX doesn't work at all, I've tried it before, in my case "disabling" the second display means it just displays nothing but the display is still on, not in standby mode. Also using SwitchResX I have this issue: apple.stackexchange.com/q/301822 Is it a problem in *nix systems to implement it?
    – Wordpressor
    Commented Oct 28, 2017 at 10:22
  • I had to build a digital signage system and had to move from Mac to a cheap PC because of the way Apple handled video. Speaking directly with an engineer at the time (school system with 1000s of Macs, we had engineering support) he said that Apple's philosophy is that it just works and they assume when you plug in a display, you want it to work. What this comes down to is wanting a Mac to do what it was never designed to do.
    – Allan
    Commented Oct 28, 2017 at 12:45
  • @Allan - I'd argue that with the advent of USB-C, which carries power AND video, the hardware is now designed to do this, but the software has not caught up so far. :-( I use my screen for two computers, the Mac and a Linux machine. But I want to keep the Mac connected to the power cable...
    – jastram
    Commented Oct 18, 2019 at 14:16
  • I do something similar, but it's with my iMac. I use a second display for work, but I want to disable that display when I game so that I won't end up with my mouse popping over there. I also have another computer that uses the same monitor, and I switch the monitor's input. But unless I pull the cord from the iMac, even with the monitor using the other input, the Mac still sees it there. So I installed SwitchResX just a few minutes ago, and it seems to do the trick.
    – Joseph Larson
    Commented Sep 17, 2020 at 16:52
  • 2
    It's a shame you have to install paid software to gain basic OS functionality
    – Petr
    Commented Feb 21, 2021 at 11:26
5

While not the best option for the op having to physically disable the display I think that is the best option. I was able to get a Geeni multiplug that I can enable each monitor individually through Google Home.

I tried the SwitchResX suggested here and it was the worst experience. I have a 2017 Macbook Pro with 4 monitors connected plus the internal display and as soon as I disabled one of the monitors, SwitchResX turned off every display and no matter what I did they never re-enabled. In the end I unplugged the 4 monitors which enabled the internal display. Then I plugged them again which did nothing and as I was looking for solutions each monitor slowly started coming back 2-3 minutes apart from each other.

Needless to say I ended uninstalling SwitchResX and sticking to using the multiplug through voice.

If you need one just search amazon for WiFi outlet. I found mine at Marshalls but I haven't seen one there ever again.

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  • Yep, I had the same experience exactly. SwitchResX is fine for resolution switching (I considered it an upgrade from Display Menu which I was previously using) but the disable display functionality is definitely flawed as described above. Pity because that's what I had been looking for. So now I'm back to pulling the connector out of the mac.
    – David Nugent
    Commented Jul 7, 2020 at 0:18
  • 1
    After checking the FAQ (no help) I contacted the author via the support link on his site, to which he responded within a few hours and asked me to uncheck "Sleep all monitors after disabling" ... and it now works fine. It is obvious when you read it but I wasn't looking for it at the time.
    – David Nugent
    Commented Jul 7, 2020 at 11:18
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Lunar can turn off an external monitor easily using keyboard shortcuts or by clicking a button.

Lunar screenshot with monitor power off instructions

There are two types of power off for external monitors:

Hard power off using DDC | Control+Command+Option+6

This turns off the monitor completely, and is equivalent to pressing the physical power button of the monitor.

It works by sending a DPMS 5 message through the Display Data Channel (DDC) protocol

Caveats
  • works only if the monitor can be controlled through DDC (some monitors block DDC/CI commands)
  • can't also be used to power on the monitor (when a monitor is turned off or in standby, it does not accept commands from a connected device)

Soft power off using BlackOut | Control+Command+6

This simulates a power off by turning down the brightness, contrast and gamma to 0, and activating mirroring to move all windows to the built-in display.

It can be toggled on and off using the same Control+Command+6 hotkey or by pressing the power button in the Lunar UI.

How it works:
  1. Uses DDC (if available) to set the native brightness and contrast of the monitor to 0
  2. Sets the system Gamma tables of the monitor to a list of zeroes
  3. Mirrors the MacBook display to the external monitor so that:
    1. The built-in display keeps its native resolution
    2. Apps/windows don't get trapped on a non-visible display

Disclaimer: I'm the developer of Lunar. Hard power off is a free feature and BlackOut is a paid feature with a free 14-day trial

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  • This should be the accepted answer in 2023 imo, great tool, love it!
    – Sejmou
    Commented Aug 8, 2023 at 9:32
2

If the work is not GPU intensive you might try to manually switch from the Discrete graphic card to the Integrated (Intel HD Graphics). Should work for all 2008-2012, 15-17" dual-GPU MacBook Pros. By installing gfxCardStatus you can do this from the menu bar.

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-2

You can just close the lid of your MacBook if you want to disable the display of this one. It is called clamshell mode: https://support.apple.com/en-us/HT201834

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  • Hmm - when you say “this one” are you meaning the external display will turn off? I think you mis-read the question, but don’t want to jump to conclusions. This seems to be a way to get the main screen (integrated / not external) as the one to work from, not to disable that screen entirely by shutting the clam shell.
    – bmike ♦
    Commented Feb 4, 2019 at 16:44
  • Ups sorry - yeah slightly misunderstood the question since the display I am working with (27") is my main display and the laptop kind of external one ^^
    – blackjacx
    Commented Feb 4, 2019 at 18:38

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