I have conneceted my Macbook Pro (Late 2011) to my recently bought 27'' monitor with an HDMI cable. I have done all the settings so when I close the lid, I can still use my external monitor without any problems.

The issue however is that my Macbook Pro heats a lot when I do that and I also use two devices and therefore have to pay bills for two devices as well.

Is there any possible way of putting my Macbook Pro into sleep mode so that I can ONLY use my external monitor without my Macbook Pro being 'on' (sleep mode)?

Extra information:

  • I use a bluetooth keyboard conneceted with a cable to charge
  • I use a bluetooth mouse conneceted with a cable to charge

Both, mouse and keyboard can be used when my Macbook Pro's lid is closed.

  • 2
    Based on your comments below I'm not sure what you're asking for. It sounds like you want your MacBook Pro to go to sleep (display and the computer itself) but you want to use the external monitor. You cannot use the external monitor if the computer is asleep.
    – samh
    May 29, 2014 at 19:29
  • 4
    I don't think "asleep" means what you think it does in this case - if your computer is asleep it's in a low-power state where it's keeping the RAM refreshed and doing pretty much nothing else (oversimplified, but that's the gist). You can't "use" the computer in this state, by definition. When you say "asleep" do you just mean that the internal monitor has been turned off?
    – Adrian B
    May 30, 2014 at 8:35
  • 2
    Using the processor, RAM, hard drive and other components is what causes heat. If you're using the computer, you're using those things. There's no way to "sleep" the heat-causing parts and still use the computer in a meaningful way. You could leave the lid open so that you get better heat flow, which would trigger the fans less often.
    – samh
    May 30, 2014 at 16:45
  • 2
    If you didn't have heat problems before the upgrade, though, there's a chance something has gone wrong.
    – samh
    May 30, 2014 at 16:46
  • 1
    So let's recap: the goal is just to shut down the mac monitor, and only use the external one?
    – o0'.
    Jul 28, 2014 at 14:50

4 Answers 4


Your MacBook Pro can't go to sleep completely as you're using it, however, since you're using it in "Clamshell mode" (with the lid shut) the internal display will have been powered down (you can tell as the logo on the lid will no longer be lit).

If you want to put the machine to sleep while it's in Clamshell mode, just press Ctrl-Eject on the keyboard you're using and the prompt for putting it to sleep will appear (the specific key sequence is Ctrl-Eject followed by 'S'). You can also put it to sleep via the Apple menu in the top left.

  • So my Macbook Pro's lid is closed and it is still working, I can hear it due to the fans working. When I see my external monitor and put into sleep from my external monitor where as the lid of the Macbook Pro is still closed, both go to sleep mode and the external monitor as well of course...
    – Doguhanca
    May 29, 2014 at 9:57
  • Ok; I'm starting to think I've misunderstood your problem. Is this answer any help? (To be clear, I've not tried it, but it seems to be what you're looking for)
    – Adrian B
    May 29, 2014 at 10:12
  • So the code sudo nvram boot-args=iog=0x0 is supposed to be entered into the Terminal. am I right? Then I have to restart my Macbook Pro and then I must do the things that you have suggested above again? That is what I have tried but it didn't work. Maybe I did something wrong :/
    – Doguhanca
    May 29, 2014 at 10:16
  • Sorry, if that's not working, I'm out of ideas.
    – Adrian B
    May 29, 2014 at 11:23

There is a little trick to do that.

Apple already has magnets build in to the lid by design.

The way to use the clamshell mode with Open lid:

To do that get a small magnet (like the one used on the Fridge) and place it on the opposite side of the lid magnets..

The magnet will simulate the lid closed.

WARNING: be very careful using magnets on your computer.

Best way to do this is

  • use a piece of iron (spoon, fork, ball pen...)

  • slowly run it around the edges of the scree till you sense the magnet pull

  • now find a magnet in you household with about same pulling force.

  • place it exactly on the opposite side of lid closing

  • I wouldn't even do that. It could harm your Macbook Pro for sure...
    – Doguhanca
    May 29, 2014 at 9:59
  • Actually there is a small magnet and sensor there already (in the lid), so when you close the lid the magnet and sensor tell your computer the position of the lid.
    – Ruskes
    May 29, 2014 at 10:02
  • Sure but there has to be a software solution to this rather than a primitive 'hardware' solution :/ Thank you though :)
    – Doguhanca
    May 29, 2014 at 10:04
  • There is nothing primitive about it, it is the state of the art high-tech way of letting the computer know the lid is closed. The magnets are in the lid. They can be located by running a piece of iron/steel along the edge.
    – Ruskes
    May 29, 2014 at 10:08
  • Sure but my question is: Is there any way of solving the problem from the software side rather than messing with the hardware? Surely there has to be a software solution. Some codes or similar to solve the problem maybe?
    – Doguhanca
    May 29, 2014 at 10:09

Put the brightness of your computer as low as possible (mine would completely dim so i can't see it) most likely using less battery power or even less than it would while the display is fully brightened. Make sure your settings are set to mirror on the display only.


I think you refer to (as other could suggested):

Clamshell mode

To execute in Terminal:

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

To undo in Terminal:

sudo nvram -d boot-args

Restart with the lid closed. After login, open the lid, the screen will be off and this "mode" won't require the adapter.

Please be aware of connecting your external monitor before turning your laptop on, or it can cause an error. Additionally, you may want to use this mode without the adapter, you can, but if you let the laptop sleeps, you will have to:

  1. Connect adapter.
  2. Close the lid.
  3. Wake your laptop up with the external input.
  4. Open the lid again.

Another reference: http://gizmodo.com/5938452/a-trick-to-make-using-an-external-monitor-with-your-macbook-way-better


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