How do I tell Lion to disable the LCD screen even when the lid is open?

The nvram trick still works for me on Mountain Lion, mid-2009 13" Macbook Pro. Thanks for the solution!

Superb, thanks Eddie. Mountain Lion, here I come... 😎

Further finding: In Mountain Lion, when the MBP goes into sleep mode and then wakes up with the lid open, the LCD screen would be turned on. It is not exactly the same behaviour in SL (the MBP LCD would stay off)...

I can't recall the exact previous behaviour in SL. However, in Lion, after using the nvram command, I have always had to reclose the lid before waking the MBP from sleep in order to leave the internal display deactivated. From what you are saying, this would therefore remain the same for those of us upgrading from Lion to Mountain Lion.

I see. I just upgraded from SL yesterday so I remember its behaviour. In SL, the internal display would stay off in such case. Too bad, seems like I have to get used to this new behaviour then. Thanks for the info.

It's so disappointing that Apple have chosen to continue to ignore this issue. All they need to do is add some options in System Preferences. So many months later and still no official recognition or solution. This was the perfect opportunity - bundle a solution in quietly with ML or let the issue persist and fester. I know which route I'd have chosen...

Sadly, I am afraid this is not working on Mountain Lion.

There has to be an app or some other way to it --- since Apple doesn't seem to care much about it anyways.

What truly frustrates me about this issue is that it's probably the simplest fix. If the behavior we are all lobbying here for was already functioning in a previous operating system, then this only proves my point more. Honestly, how many users need to complain about this issue before Apple does something about it?

Apple, use common sense. There are obvious benefits to using the computer with the lid open. Instead of having your customers do the work, how about you set up a MacBook Pro with an external monitor, keyboard, etc. and do some testing yourself? The antenna array--focusing particularly on the WiFi antenna--are located directly under the hinge of the laptop screen. I'm currently using my laptop with an external keyboard and mouse in a part of my house where if the lid is OPEN the signal is fine. If the lid is CLOSED I get no signal. It's simply outrageous that I can't leave the lid open and use only the external monitor. It actually disgusts me to think I have to complain in order for this feature to come to fruition.

APPLE, DO SOMETHING ABOUT THIS AND PLEASE YOUR CUSTOMERS. When it comes to these simple things, you're the most thickheaded company I've ever dealt with. Why don't you just make us all happy? We're asking you to bring back an industry standard feature!

Hi, Everyone

Thanks a lot for Godoy12 for the trick !

Confirmed on my MacBook Pro late 2011 (15", core i7 2.4Ghz) + OSX Lion 10.7.4, no nvram command, no magnet, 100% easily reproductible 🙂

You don't even need the "active corner" trick

Here are the steps:

1) Connect your external screen + plug-in AC power on your MBP.

2) Ctrl+shift+eject -> Will put monitors to sleep

3) Close the lid

4) Wait at least 3s (you only have to wait enough for it to switch mode, 3s was enough for me)

5) Reopen the lid and only your external screen will wake up, there you have "open clamshell mode" 🙂

To reactivate your internal monitor, either do "Detect Monitors" or close/reopen your lid again.

To see if it's worth it, I ran my usual music production app which runs on CPU not that heavily but constantly and checked the temperature and fan speed

- Clamshell mode : full 747 turbine (6200rpm or so)

- Open lid with internal screen turned on ~4500rpm

- "Open clamshell" trick ~4000rpm

When the speed stabilizes the temperature is around 70° in the 3 tests.

4000rpm is still noisy but significantly better

Laurent

Laurent,

Are the displays mirrored?

Following your instructions, I get aout 5 seconds of external display then the MBP display comes back on andIm back at 1200 x800 on both.

Please advise. Late 2011 13" MBP MD314/LLA 2.8GHz dual core non retina

Thank you,

Ben

Message was edited by: MonochromeB

Hi, Ben,

Sorry this did not work out for you 😟

On my setup I'm able to do it whatever the screen is in mirror or extended mode.

I was thinking this could be the resolution difference between your MB and your monitor (my external display has the same res as the MBP display which is 1680x1050), I tried to change the res on my MBP to 1200x800 to verify, but it still worked, when I do the trick, I have my monitor alone at full resolution.

Are you sure you waited long enough before reopening the lid ? I ask because what you describe (5s of monitor display, then switch back to both monitor and internal displays) is what happens when you reopen too quickly.

The last thing I can think of, is that the 15" has 2 graphic chips , the Intel HD + a dedicated AMD Radeon (which is automatically used when connecting an external display) , I'm not sure the 13" model has the dedicated one does it ?

Laurent

Laurent,

Thanks for the followup.

The 13" has the Intel HD and no other separate chip. Makes sense to me now.

As much as I hate it, I researched and ended up placing a small magnet over the 'clamshell closed' sensor (on the 13, directly above the headphone jack, and it turned my MB LCD off and allowed me to use a BT keybd and mouse to interact with the external display. When I remove the magnet, the MB LCD comes back to life and I power down the external.

Just for continuity of the test, I am going to try your method again and increase the wait time. Will report back.

Ben

Apple, we need an option to keep the lid open because MacBooks overheat. They do. Their fans spin and their temps go to 100 Celsius. Isn't that enough? Is this good for the LED display? Is it good for internals of the machine? And why have the screen on anyway if it's hidden from view? Clamshell mode....

The easiest way to run your MacBook Pro 13" with the lid open yet the display off (the computer then will allocate all graphics processing power to your external display because it thinks it is in clamshell mode) is to use a magnet. I went to harbor freight and purchased a generic magnet, it is about 2" long 1" wide and 1/2" high. I wrapped it bright orange duct tape to protect the finish of the MacBook Pro. When I want to use my external display but operate in clamshell mode (or so the computer thinks) I leave the lid open and place the magnet on the left side corner edge. It works when the magnet is placed on the edge directly over the built in battery charge remaining indicator). This is using a late 2011 13" MacBook Pro, for other models you may have to play with the placement of the magnet (my late 2007 MacBook Pro the magnet placement is totally opposite). I chose this method because I did not like SwitchResX software option when a $1.00 magnet works just as well without glitchy software.

The ctrl-shift-eject trick never worked for me on either my mid-2009 MBP or the mid-2012 I just got. Both monitors would always wake up again.

The nvram trick worked after a reboot on my mid-2012 (15", Lion 10.7.4, model 9,1).