Turn off both displays when in clamshell mode I've been using this Macbook Pro for about 2 years now and recently got an external display for it. It is connected via a Thunderbolt to HDMI adapter.

Before I got the display, I could simply shut the lid to enable clamshell mode and the system would mostly power down (HDD would stop etc).

However, now whenever I shut the lid, the external monitor becomes the primary display and continues to work and keep the laptop awake. I do not have an external mouse, trackpad or keyboard connected.

Is there any way to make the laptop go back into clamshell when the lid is shut and turn both displays off? I would prefer if it were possible without disconnecting the external display, as every time I do that I lose my window arrangement across displays.

I found this, but I don't want point two. I want both displays to wake up when I open the lid, and both displays and the mac to sleep when I close it.
You are confusing sleep and clamshell mode. Clamshell mode means using a laptop with an external display while keeping the lid closed.

Anyway, clamshell mode behaved differently in 10.6 and earlier:


Closing the lid put a laptop to sleep even when the laptop was connected to an external display
To use the laptop in clamshell mode, you had to press a key or click a mouse button after that
If you then opened the lid, the internal display didn't turn back on


You can restore the old behavior by changing the boot-args firmware variable:

sudo nvram boot-args=iog=0x0


You have to restart to apply changes. To undo it, run sudo nvram -d boot-args and restart.