I went through a similar question, but the answer was informing how to hide the monitor, but not how to disable it.

I do not want any new windows to creep into the laptop display when the external display is connected. I could not find any in the Display Settings (under System Preferences).

I don't want to close the lid because I think it impacts the air flow of the MacBook Pro.

I don't want to close the lid because the sound quality is reduced.

17 Answers 17


Reducing heat by adjusting the lid

Having the lid closed or open does not impact the airflow of your MacBook Pro (MBP). Ambient air is never in short supply and the "exhaust" (where the hot air picked up by the blade fan(s) are expelled) is located at the back of the unit (the black stripe on the newer models and the grey stripe on the first generation machines).

Some claim that keeping the lid open allows the chassis to cool down, but these claims have never had any real data behind them (simply anecdotal evidence and unsubstantiated rumour). Personally, I have a 2006 MBP that was eventually relegated to being a desktop. I ran the system for well over a year with the clamshell open, and then closed, and saw no different in CPU/CPU temps (nor any variability in the other heat sensors) as a result. Moreover, the newer models have far more efficient blade fans and would suffer even less from the effects of heat (additionally, the new Intel chipsets run cooler than their predecessors). You can conduct your own testing of course. I had replaced the heat sink, re-applied a sane amount of Arctic Silver thermal paste, and used Lobotomo Fan Control daemon to monitor my system's temperature.

Disabling the internal display, properly

There are two ways to connect a secondary display to your notebook without enabling the default screen (note that this does not mean dimming it, but rather turning it off).

  1. The first is to connect the display with the lid closed when the machine is powered down. Once the external display is connected, turn the machine on—it will detect the secondary display while leaving the internal one turned off. This will alleviate the issues you have with "dragging things off the screen" as the system will constrain your desktop to the one, active monitor.
  2. The second is to connect the secondary display when your system is awake and active, and the clamshell open. Make sure the notebook is plugged in. Once you connect the secondary monitor, the system will recognize it. Once it does, close the lid on your notebook. The device will be put to sleep. Once that happens, move your mouse, or hit a key on your keyboard to wake it. Once it wakens, it will enable the secondary display, but not the internal one.

Additionally, you may set the attribute to leave the system in the sleep state even if the clamshell is opened. You can do this using pmset, a local utility found on OS X that actually handles all your power settings. You can accomplish this with the following command:

sudo pmset -a lidwake 0

The -a, -b, -c, -u flags determine whether the settings apply to battery ( -b ), charger (wall power) ( -c ), UPS ( -u ) or all ( -a ).

To reverse the command, set the 0 to a 1. These settings are persistent, in that, they do not need to be re-applied every time the machine's power is cycled and are saved to the file: /Library/Preferences/SystemConfiguration/com.apple.PowerManagement.plist

  • 5
    The command pmset doesn't work on El capitan 10.10.2. Any alternative?
    – Fred K
    Commented Dec 16, 2015 at 16:01
  • 9
    "Once the external display is connected, turn the machine on" on a Mac laptop, that involves opening the lid/clamshell though.
    – Adriano
    Commented Feb 8, 2016 at 5:45
  • 3
    The two ways mentioned in this answer just do not work in MacOS 10.13.
    – sgon00
    Commented Nov 30, 2018 at 14:07
  • 4
    To use option 2 your laptop has to be plugged in. FYI: Having the lid closed will generate more heat. Part of the aluminum body design is that it dissipates heat through the top case. But no matter. Commented Jan 19, 2019 at 22:56
  • 3
    You don't even need a thermometer to test that the laptop gets hotter with the lid closed. Just touch it. And the fans spin louder. The LCD portion is generally completely cold when you touch it when the lid is open. When LCD is closed, even though there are no holes (aside from keyboard) on the front, the heat is escaping through the metal (it acts as a heatsink). And when the lid is closed that heat is trapped inside and is transferred to the LCD. You can warm up the laptop to test this by running some CPU-heavy tasks like video rendering, or even playing some hi-res videos.
    – Emil
    Commented Mar 13, 2021 at 1:36

You could also use a ThirdParty App like https://github.com/Eun/DisableMonitor/


DisableMonitor adds the missing feature to disable a monitor on a Mac. You can also easily disable, enable or change the resolution of a monitor. enter image description here

  • 2
    Answers on Ask Different need to be more than just a link. It's okay to include a link, but please summarize or excerpt it in the answer. The idea is to make the answer stand alone.
    – nohillside
    Commented Sep 29, 2014 at 13:32
  • 1
    Probably you have not noticed: this is an old thread, my thread is just for completeness, why writing more than necessary?
    – Eun
    Commented Sep 29, 2014 at 14:05
  • 2
    Answers are more likely to help other users if they explain a bit more about the solution you are proposing. Also please have a look at self promotion in the FAQ.
    – nohillside
    Commented Sep 29, 2014 at 14:31
  • 7
    This application reduces the brightness of the monitor to 0, but it remains on! So probably it consumes more. Is there a way to completely turn off?
    – Fred K
    Commented Dec 18, 2015 at 10:13
  • 5
    PLEASE READ THE WARNING IN GITHUB: It has been reported that the software is able to cause irretrievable damages to your computer. Use at your own risk!
    – Farshid
    Commented Apr 8, 2019 at 17:46

My suggestion is to set the displays to 'mirror' then turn the brightness down on your Mac.

Both your screens are the same so you won't lose any windows.

  • 3
    mirroring wont give me the same resolution. even at 0 brightness, you can see the screen. My problem is that keeping it open blocks a view. hence need to close the lid
    – Sairam
    Commented Oct 23, 2013 at 3:59
  • 9
    In such way, the built-in display still uses hardware/software resources. Turning brightness down does not help anything except you can't see it.
    – sgon00
    Commented Nov 30, 2018 at 14:09
  • Fantastic, simple, and it worked! Thanks! :)
    – yazz.com
    Commented Jun 20, 2019 at 7:26
  • yeap, that's perfect. It even gives you an option which monitor to optimize resolution for 👏🏼
    – Zapko
    Commented Feb 11, 2022 at 18:11
  • With models where the monitor goes 100% dark at lowest brightness, this is a superb solution. I'm not sure why anybody would seek further. By mirroring one of the external displays to the build-in display, you prevent the extra dragging and window out-of-sight issues. In summary, this was precisely what I was after: laptop screen is drawing zero power, mouse leaving the screen not an issue, external resolution is perfect even though ultra-wide, and laptop keyboard and trackpad are still primary input. 5/7 perfect!
    – theherk
    Commented Dec 7, 2022 at 11:46
  1. Cmd + F1 (switch one display mode - laptop display will turn into mirror of external display)
  2. F1 (until you turn off laptop display)
  • 3
    Holy moly. This actually works! And it disables the internal display; windows are moved to the external display only. The instructions are not super clear though: 1. Press Cmd + F1 (usually two times) until the screen is mirrored to both screens. 2. Press F1 to disable the internal display. 3. Profit.
    – sun
    Commented May 21, 2021 at 20:43
  • Doesn't help with MacBook Pro 16" where the Radeon graphic card (5300 or 5500) runs at 18w instead of 6w when not in clamshell mode or just internal monitor. Commented Sep 23, 2021 at 20:00
  • 1
    Best answer. I was on the side of forcing it with some open source sw or terminal command but this is just simpler and a safer bet
    – sogu
    Commented Dec 31, 2021 at 16:20

Update 2017 & Sierra (OSX 10.12.6+)

I didn't find any working solutions in order to configure this on Sierra so I'm posting this for people looking for a solution in 2017.

This should allow you to use your Mac with an external display, external keyboard/mouse or even the built in keyboard including (the very useful) fingerprint scanner and lcd touch bar on newer models.

Here's how I got it to work:

You need to run this command: nvram boot-args="niog=1" but it's not going to work unless you boot into recovery first. It'll give you garbage like this instead:

nvram: Error setting variable - 'boot-args': (iokit/common) general error

To fix this we need to boot into recovery and disable SIP.

  1. Reboot and hold down CMD + R during boot. When it loads, chose your language and use the top navigation bar to go to Utilities -> Terminal
  2. Use csrutil disable command to disable SIP.
  3. Reboot normally.
  4. Open terminal and use the sudo nvram boot-args="niog=1" command
  5. Reboot and close your lid, keep it closed until you've logged in and see your desktop.
  6. Open your lid and the laptop display should stay OFF.
  7. IMPORTANT: Go back to recovery (reboot with Command + R) and re-enable SIP using csrutil enable
  • this is by far the best answer, works like a charm in Mojave, thanks!
    – Tiago
    Commented Jun 29, 2019 at 11:19
  • Best answer, works for me. Just a side note: There is no need to use sudo within the recovery, I think you are root anyways. Also, note for myself: nvram boot-args="niog=1 -v" to also get the juicy verbose boot logs rolling by during boot. Lastly: If you use FileVault encryption, you have to close the lid after entering your password again to make things work properly. Nice! Commented Feb 17 at 0:27

My question finally answered by running:

 sudo nvram boot-args="iog=0x0" 


  • 4
    It does not seem to work any more. I am using Macbook Pro (Retina, 13', Mid 2014) with 10.10.2.
    – Lex Li
    Commented Feb 20, 2015 at 4:10

I finally found a way to disable the main monitor instead of hiding it for any number of external monitors. I'm saying any number because the mirroring option suggested by other answers mirrors all displays. If you have two external monitors like me, you would find that it doesn't help at all.
You'll need SwitchResX for this (yes, it's paid, but it you don't pay it just annoys you with a warning every day and disables some features, that's all). One thing I want to point out is that the 'disable screen' option just hides the screen and it keeps rendering in the background, which is not what we want, instead we will mirror one of the displays on the built-in one:

  1. Go to video mirroring in the switchresx menu and mirror the built-in display on any of your external monitors
    mirror a display

  2. You might have to set your external display resolution if it displays the wrong resolution
    set external display resolution

  3. Turn off the brightness on the built-in display if you want to

You will see that it's actually mirroring the display if you look at preferences > display > arrangement:
enter image description here And looking at the GPU memory usage, I can confirm again that it's not rendering the built-in display, which should mean much better performance and much quiter fans! memory usage

  • This worked for me with multiple external monitors. Great! Thank you.
    – musemind
    Commented Jan 27, 2021 at 10:39

Solutions using Magnets for MacBooks (2015-2019)

There might be many reasons you would want to turn off the built-in display of the MacBook. I am using two larger external monitors, and while using heavy applications if 3 screens are active the Mac starts to throttle. For myself personally, the smaller built-in screen is taking unnecessary resources so just reducing the brightness to zero is not an apt solution. And neither is closing the lid since I was having connectivity problems with my Wifi on the 2.4 GHz channel when the lid was closed and I also want to use the magnificent built-in trackpad for gestures rather than buying an external one.

I was looking at a lot of answers in forums and in this thread but unfortunately, most software-based solutions are outdated and don't work and applications like DisableMonitor say :

It has been reported that the software is able to cause irretrievable damages to your computer. Use at your own risk! The project development has been stopped and won't be continued.

My Setup

I am using a 2019 15" MBP and this solution worked for me. I am hoping this solution would work for all devices in this design platform that Apple used starting from 2015-present (2021).

What you need

We need 2 small low powered magnets. Unfortunately, the magnetic strip used in refrigerator magnets did not work for me.

Magnets that I used were from cheap old IEMs (Earphones), they were perfect since they were relatively low power and I got two of the same size and power.


We are trying to simulate what MacBooks do, to know that the lid is closed.

Two of the many magnets in the display lid in the MacBook in combination with Hall effect sensors in the lower chassis are used by the Mac to determine when the lid is closed. So all we need to do is place 2 magnets on the lower chassis at the exact location where the two magnets in the display would have been when the lid is closed and voilà it works.

One thing we need to take care of is to place both the magnets at the exact same time otherwise, it doesn't work.


Place the two magnets at the exact same time near the edge of the chassis. For the 2019 15" MBP the location is just below the 2 USB-C ports on either side.

enter image description here


The new Macs do not use any moving parts and especially the hard drives are SSDs, so that concern is for the most part alleviated. Also since the Apple laptops themselves are using magnets to know if the lid is closed it seems to be a safe enough solution as long as it's used when the MacBook is kept stationary and using low-power magnets. Also, I do not see any distortions in the audio while using the built-in speakers as long as the magnets are low in power.

This is one of the only solutions that worked for me which is quite straightforward. Since we are using magnets around computers, I would recommend using as low powered as possible and also check if your computer is using any hardware internal or external which can be affected by magnets (eg, magnetic hard drives) and do after your own research the last thing we want is someone to destroy their work or damage their hardware.

Update after 1 month.

Based on the concerns shown in the comments: using magnets can be dangerous in that if one forgets they are there and closes the lid the display can be cracked.

I have modified my solution as in the pictures bellow :

Attaching the 2 magnets to a piece of packing material which is cut in the exact size of the MacBook and the magnets are glued in position, so that they align perfectly with there intended place on the laptop when the material is placed on top of the laptop.

enter image description here

Description : The magnets are glued into correct place.

enter image description here

Description : The spongy-material is placed with the magnets side facing down, so that the magnets align perfectly with there intended position and if there is any accidental closure the material will absorb the shock.

It gives two advantages:

  1. Obviously the concern of accidental screen closing and the worry of the screen cracking is resolved.
  2. An added advantage is now we don't have to go through the trouble of carefully placeing the magnets at the same time, just placing the sheet in the correct location is enough, it reduces the hassle significantly.

Pro Tip: I find sliding the sheet into place much easier. Also you might have to place something with a small weight on top of it especially for the first few days so that the sheet does not bend.

  • 1
    Using magnets are dangerous in that if one forgets they are there and closes the lid the display can be cracked. I'd find a different solution than using magnets. Commented Sep 23, 2021 at 17:07
  • 2
    Valid point but the solution is the only one which works to recreate clamshell mode on the MacBook Pro 16" where the Radeon 5300 and 5500 run at 18w instead of 6w unless operated in true clamshell mode or without external display. Apple isn't making it easy.I agree about the magnets being a danger to the screen. The magnets should be painted bright red or bright yellow and have soft rubber or felt caps on top. Commented Sep 23, 2021 at 20:07
  • 1
    I'm looking this up today for my 16 inch mbp and you wrote this just yesterday, quite a coincidence ! Commented Sep 25, 2021 at 10:33
  • I love this solution but I cannot make it work on a 16" model. If anyone had any luck could you post a picture of where you put the magnets? I used to put to sleep the 2015 models all the time with the magnet on my milanese loop ...
    – Enrico
    Commented Mar 21, 2022 at 9:24

Here's a visual answer that should help folks quickly find the solution:

1. Select "Mirror Displays" in the "Arrangement" tab

You can find that "Arrangement" tab in the "Display" section of "System Preferences" whenever an external display is recognized.

enter image description here

2. Ensure it's optimized for the external screen

This should be default, at least it was for me.

enter image description here

3. Lower the brightness of the MacBook down to Zero


Do as described here:

How can I turn off the screen on the macbook when I have an external monitor set up?

Then open the laptop.

In Snow Leopard this will do what you are asking for. The behaviour may have changed under Lion though. Which OS version are you using?

  • I saw the answer, I wanted to see if there is a better way than this.
    – Sairam
    Commented Aug 13, 2011 at 11:09
  • Try the keystroke combo Ctrl-Shift-Eject. Does that turn off both monitors or just the internal one?
    – dan8394
    Commented Aug 13, 2011 at 11:13
  • The above combination restores to the previous state
    – Sairam
    Commented Aug 13, 2011 at 12:23
  • 1
    Sorry Sairam - I don't understand you. State of what?
    – dan8394
    Commented Aug 13, 2011 at 12:36
  • When I try Ctrl-Shift-Eject , it turns off both monitors and internal one .
    – Sairam
    Commented Aug 13, 2011 at 17:13

Lunar can turn off the MacBook display without having to close the lid of the MacBook.

Lunar screenshot with instructions for activating Blackout

This allows the MacBook to cool down faster and allows you to keep using TouchID, webcam and the very nice speakers of the MacBook, while being able to focus on the external monitor.

The feature is called Blackout, here are some more details: lunar.fyi/#blackout

How it works:

  1. Sets the native brightness of the MacBook display to 0
  2. Sets the Gamma tables of the MacBook display to a list of zeroes
  3. Mirrors the external monitor to the MacBook display so that:
    1. The monitor keeps its native resolution
    2. Apps/windows don't get trapped on a non-visible display

To activate, just press Control+Command+6 and Lunar will toggle Blackout and do all of the above steps for you.

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

  • 4
    FYI: blackout is a paid feature
    – Sairam
    Commented Aug 22, 2021 at 13:54
  • I have experimented with my external 29" LG monitor which, unfortunately, does not provide enough voltage with Type-C cable, as I know, but even turning off the MacBook monitor does not solve high battery drain problem.
    – A.Ametov
    Commented May 3 at 19:20

When I had my MacBook Pro connected to an external TV, I used the magnet trick.
Placing a small weak magnet (I used one the size of a coin battery) near the bottom of the right speaker would make contact with the Reed Switch, tricking the MBP into sleep mode, with the lid open, while using the external display only.

While this worked fine for the time I had the external TV and I never read any reports about this technique damaging anything (there ARE magnets inside the MBPs), I would try a software based solution, first.

Some references:

iBook and PowerBook Clamshell Sleep Control
Location of magnet and Reed Switch for various Mac laptop models and instructions on how to use both a magnet to force sleep with the lid open or a thin piece of iron alloy to prevent sleep with the lid closed.

Reed Switches
Location of magnet and Reed Switch for the MacBook Pro 15" with pictures.

  • The magnet is the only thing that works with the new OSs. Those commands used to work in the past, but stopped working for some years. Locating the spot should be fairly easy by moving a small magnet along the surface of the laptop where the bezel of the screen meets. Use the side of the magnet that attracts metal. On my MacBook pro 2014 model the spot is to the left of the keyboard closer to the top. But it’s fairly easy to locate if you move slowly. Just use any normal magnet, not the very strong type they use inside hard drives.
    – Emil
    Commented Feb 19, 2021 at 18:50
  • 1
    Please don’t down-vote this Answer. It’s one of a few working solutions I’ve found that works reliably. And if you’re wondering that this may cause damage, well the mechanism is designed to respond to magnet by Apple. There’s a magnet in the screen. 3 of them in fact on mine, 2 for the lid to keep shut, and one for this sensor.
    – Emil
    Commented Feb 19, 2021 at 18:54
  • 1
    “Closing the screen” solutions also work, but that makes laptop hotter, and prolonged heat can (unlike small magnets) damage the hardware or at the very least cause CPU to function less efficiently. Especially in warm environments.
    – Emil
    Commented Feb 19, 2021 at 18:58

I write a simple App

Close Inner Screen

It can be easy use

enter image description here

  • 2
    Hello, can you please add some details on how it works? Are there any risks? Does it involve turning off SIP?
    – trusktr
    Commented Jun 7, 2019 at 21:42
  • This app just turns down the brightness, which means windows can still open on the now black screen.
    – Fuzzy76
    Commented Mar 16, 2020 at 17:21
  • GreatApp. it work for me
    – 能蟹仔
    Commented Nov 12, 2022 at 0:02

Update for MacBook Pro 2018 running macOS 10.14.5

I found a solution that works quite well for me

  1. Set external display as primary display (by dragging the menu bar in the Displays setting in System preferences)
  2. Check the box to Mirror Displays
  3. Turn down the brightness all the way on the clamshell display

This doesn't quite disable the clamshell display, but it won't actively consume any applications, and setting the brightness to 0 provides an energy efficient way to ignore the mirrored display.

  • The issue here is that you run into Image Persistence. See here from Apple on how to avoid it: [Avoiding image persistence on Apple displays] (support.apple.com/en-us/HT202580) They suggest "Set the "Turn display off after" slider to a brief interval, like 15 minutes." This is not possible when you are actively working with an external monitor and keeping your laptop open. Commented Jul 22, 2020 at 20:40
  • 1
    How can you run into Image Persistence when the laptop screen is mirroring everything you do? (even when brightness is zero, so it is just you can't see it)
    – Osmar
    Commented Dec 3, 2020 at 15:05

You can also make the external display the primary one. By default all new windows will appear on that one. To do this, go to system preferences > Display > geometry, and drag the miniature menu bar to the miniature external display.

  • I tried that as well. Some applications I rarely use, tend to open windows on the laptop display.
    – Sairam
    Commented Aug 15, 2011 at 5:06

Simply closing mac's display when an external monitor is still on worked for me.

My setup:

  • MacBook Pro Sierra 10.12.6
  • External monitor connected through HDMI & monitor USB cable
  • External mouse and keyboard connected to the monitor
  • Also works on MacBook Air M1 with Ventura 13.5 (keyboard, mouse and monitors connected through a docking station), this is indeed the simplest solution.
    – max-lt
    Commented Nov 26, 2023 at 9:32

for mac users trying to use hdmi to tv and having troubles turning off your screen on laptop and leaving screen on tv on, TURN THE BRIGHTNESS RIGHT OFF!!!! the laptop screen will go black but tv screen stays the same

  • 7
    This doesn't prevent windows from begin dragged on to the turned off display. It's nice for saving power and bulb life of course, just not so much an answer to the problem here.
    – bmike
    Commented Dec 28, 2013 at 20:40
  • 1
    Also the screen doesn't go completely black. In low enough lighting the screen is still visible.
    – Arc676
    Commented Jan 7, 2016 at 13:29
  • On my 2012 MacBook Pro with OSX Sierra it works perfectly.
    – Martin Cup
    Commented Nov 23, 2017 at 21:12

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