What software to disable the internal display when using external monitors?

[Fomalhaut]

I would like to disable my Macbook's internal display (MBP14) when I am using external displays to prevent the internal display forming part of the extended desktop. I would prefer not run in clamshell mode to allow for better cooling.

I have tried SwitchResX and Lunar, but neither seem to have an option to disable a screen that works with M1 Macs.

Does anyone know of any 3rd party software that actually works?

 

[chscag]

I don't believe you can disable the internal display unless you use clamshell mode which you say you don't want.

I ran my MacBook for years in clamshell mode and never noticed a difference in cooling. But, that was a long time ago with a much less powerful Intel machine.

SwitchResX and Lunar are great for changing resolutions but as you say, they don't provide shutting off the display.

 

[hovscorpion12]

There are two ways to have the MacBook display black screen when connected to external monitor.

Option 1.
- Plug in your MacBook
- Go to System Preference and click mission control.
-Click on Hot Corners and click on one of the corners. Once selected, pull down the menu next to it and choose Put Display To Sleep.

Connect the external display to your MacBook and then move your mouse to the corner you selected above. It should turn off only the internal display. Close your MacBook lid and wait a couple of seconds. Lift the lid and it should stay off.

Option 2.
- Open Terminal
- Paste sudo nvram boot-args="iog=0x0
- Type in your main password when prompted. You’ll need to restart your MacBook. Make sure it’s connected to the external displa. This will shut off your internal screen until you use the following command to change it back:

sudo nvram -d boot-args

Then reboot again. If you accidentally disconnect the MacBook from the display, you’ll need to zap the pram, which entails holding Command-Option-P-R when restarting.

 

[Fomalhaut]

I don't believe you can disable the internal display unless you use clamshell mode which you say you don't want.

I ran my MacBook for years in clamshell mode and never noticed a difference in cooling. But, that was a long time ago with a much less powerful Intel machine.

SwitchResX and Lunar are great for changing resolutions but as you say, they don't provide shutting off the display.

Thanks for the reply. I may be worrying unnecessarily about clamshell mode, particularly with the new MBP14, which will run cooler than my previous MBP16 - that get really hot on the metal strip above the keyboard, and I did notice some potential issues with the screen coating, although I can't determine whether it was due to heat, some object trapped between screen and keyboard, or someone touching the screen at some point.

 

[Fomalhaut]

There are two ways to have the MacBook display black screen when connected to external monitor.

Option 1.
- Plug in your MacBook
- Go to System Preference and click mission control.
-Click on Hot Corners and click on one of the corners. Once selected, pull down the menu next to it and choose Put Display To Sleep.

Connect the external display to your MacBook and then move your mouse to the corner you selected above. It should turn off only the internal display. Close your MacBook lid and wait a couple of seconds. Lift the lid and it should stay off.

Option 2.
- Open Terminal
- Paste sudo nvram boot-args="iog=0x0
- Type in your main password when prompted. You’ll need to restart your MacBook. Make sure it’s connected to the external displa. This will shut off your internal screen until you use the following command to change it back:

sudo nvram -d boot-args

Then reboot again. If you accidentally disconnect the MacBook from the display, you’ll need to zap the pram, which entails holding Command-Option-P-R when restarting.

Thanks for that!

Unfortunately, Option 1 doesn't seem to work for me. The hot-corner display sleeps shuts off both screen, and closing the lid and opening causes the laptop screen to display again. This may be a property of the screen I'm using (Dell U2715H)

Option 2 sounds interesting, but a bit of a hassle if you accidentally disconnect the external screen. I can see that it would be good for a setup where you don't need to disconnect the laptop often though.

Thanks for your answers though

 

[ennojacobsen]

This may be a simple solution to the problem: Turning down the display brightness manually via the keyboard (by pressing F1) should make it possible to turn off the laptop screen, while leaving the brightness on external displays unchanged.

 

[BrianBaughn]

You could look into BetterDisplay. I'm using the free version and don't really know what the capabilities of the paid ($15) version are…but I do see mirroring options and I'm wondering if you just mirrored one of the external displays to the built-in one if your arrangement would end up as you wish. There's a trial period so you can check out the paid features.

GitHub - waydabber/BetterDisplay: Unlock your displays on your Mac! Flexible HiDPI scaling, XDR/HDR extra brightness, virtual screens, DDC control, extra dimming, PIP/streaming, EDID override and lots more!

Unlock your displays on your Mac! Flexible HiDPI scaling, XDR/HDR extra brightness, virtual screens, DDC control, extra dimming, PIP/streaming, EDID override and lots more! - waydabber/BetterDisplay

github.com

 

[gajendrajena]

You could look into BetterDisplay. I'm using the free version and don't really know what the capabilities of the paid ($15) version are…but I do see mirroring options and I'm wondering if you just mirrored one of the external displays to the built-in one if your arrangement would end up as you wish. There's a trial period so you can check out the paid features.

GitHub - waydabber/BetterDisplay: Unlock your displays on your Mac! Flexible HiDPI scaling, XDR/HDR extra brightness, virtual screens, DDC control, extra dimming, PIP/streaming, EDID override and lots more!

Unlock your displays on your Mac! Flexible HiDPI scaling, XDR/HDR extra brightness, virtual screens, DDC control, extra dimming, PIP/streaming, EDID override and lots more! - waydabber/BetterDisplay

github.com

BetterDisplay solves the problem elegantly.
With the latest version, this is a very simple feature.
Thanks @BrianBaughn for the answer, and kudos to [@waydabber][https://github.com/waydabber]

 

[Abedoss]

You could look into BetterDisplay. I'm using the free version and don't really know what the capabilities of the paid ($15) version are…but I do see mirroring options and I'm wondering if you just mirrored one of the external displays to the built-in one if your arrangement would end up as you wish. There's a trial period so you can check out the paid features.

GitHub - waydabber/BetterDisplay: Unlock your displays on your Mac! Flexible HiDPI scaling, XDR/HDR extra brightness, virtual screens, DDC control, extra dimming, PIP/streaming, EDID override and lots more!

Unlock your displays on your Mac! Flexible HiDPI scaling, XDR/HDR extra brightness, virtual screens, DDC control, extra dimming, PIP/streaming, EDID override and lots more! - waydabber/BetterDisplay

github.com

Signed in just to thank you.

Thanks

 

[zorinlynx]

Clamshell mode is not an issue with regard to cooling on Apple Silicon Macs. They have much better thermals than previous Intel Macs so issues you had with clamshell mode on Intel Macs simply don't apply to Apple Silicon.

I know, I know... there's a lot of PTSD among the Mac community from how bad thermals were under Intel. Those days are gone now, and you can rest easy.

(BTW, does anyone notice a slight delay when typing punctuation at the end of a sentence? It happens with both ? and . and I could swear only started happening recently.)