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

Have you tried the terminal command trick here: https://discussions.apple.com/thread/3190417?answerId=16059565022#16059565022

I would really like to know if this still works in 10.8.3 before I update.

Also tried chenga's trick (sudo nvram boot-args="iog=0x0" then reboot) but it doesn't work on 10.8.3. Both fullscreen app trick and chenga's command line trick doesn't work now. Makes me wonder if Apple is monitoring this thread. 😉

Is Apple doing this on purpose or what?

My app was exploiting a bug in OS X, so it's no surprise it was fixed. The speed of which they fixed it was very surprising - especially for such a minor bug.

Anyhow, I've made another app that disables a secondary display. Could someone please try it out and let me know if it works for you? It doesn't actually turn off the display entirely - it mere disables it. Exactly like SwitchResX does. And like SwitchResX, it needs to be running all the time :-(

Try a alpha version here: http://www.seph.dk/download/Clamshell%20mode.app.zip

Let me know if it works for you.

It does and it doesn't.

The display is off, so that's good, but it's still "there." if i move my mouse off the screen it goes to the next screen.

I am using "Mavericks" 10.9 DP1, seems SwitchResX cannot put my internal Display to sleep. Is there Ok to sleep the Internal screen in 10.8.2 by using SwitchResX? My computer is Retina 13. If this app will work in 10.8.2, I prefer downgrade my computer, the New feature "multi-display" in 10.9 which is good, but still not useful for a man prefer to use on single large monitor (just like me) ... Thx for replying ~~

If you are a developer and running a legitimate copy of a not yet publicly released OS, you are aware that you are violating your NDA by discussing it in a public forum? You need to use the special forums available to you.

Thanks for warning, but I do hope Apple adds an disable Internal option for users. 🙂

Year, it still not working in 10.8.3 and 10.9 DP1(which I recently upgrade to try) , and the full-screen game trick is not working too. Maybe I need to downgrade my Mac to 10.8.2 and try, BTW, my computer is Late-2012 13" with Retina display. I've done most of my work in my external display. I am sure my computer will burn down if I close my lid all the day, and My screen retention must be shwon up if I open the lid and remain the same image in all day.

Soooo....

Apple is annoying, The apple engineer fix these Clamshell "bugs" very soon and high quality. I was wonderying, why they're so mean to there customers? Or maybe they just put their minds on how to make a Macbook with no Overheat problem instead of cutting our rights of contorling our own screen !!

The annoyance of Apple taking away that feature was one of the factors that I considered last year when I decided to retire my desktop computer and go laptop-only. A 15" MBP Retina Display was certainly on the shortlist to take the place of my 2007 vintage MBP, but the winner was an HP Envy 15, on which I installed Ubuntu. To be sure, Linux has rough spots of its own, and the HP has a couple (keyboard is good, but not as good as Apple's, and the touchpad isn't as good as Apple's, either), but I'm happy with it, and I can control an external monitor as I see fit, from right in the control panel. No tricks needed. My OS is working for me, not against me.

That doesn't mean I won't keep buying Apple products. My wife and kids all have MBPs, my wife and I both have iPhones, and she also has an iPad 3. Whenever she finally decides to retire her 6 year old MBP, a MacBook Air is on the shortlist. I use a Mac at work (and Linux, too), but I'm likely to be a PC notebook buyer from here on out. Going 100% Linux has been refreshing. Apple could learn a thing or two from Ubuntu.

In OSX 1.8.3 my MBP internal screen is sometimes disabled. However I don't know the replication steps, it involves certain steps before waking up the MBP from sleep somehow but I have not been able to find the exact replication step. Maybe one of you can find out how this is done. Good luck!

didn't work anymore in mountain lion

chenga.8's advice to enter:

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

at the command line worked for me on OS X 10.8.3 / Mountain Lion to solve the problem of my MacBook Pro not going to sleep when I use an external monitor, which is attached with Apple's Mini DisplayPort to Dual-Link DVI Adapter, which sends D-LINK to a high res display.

Thanks, chenga.8!

-macison

Really? Confirmed? The boot-args actually didn't work in 10.8.3 any longer. Would be a surprise to me if they changed or fixed it with one of the later minor updates.

Yes, I just reconfirmed. I'm running 10.8.3 on a MacBook Pro, and when I shut the lid, the monitor turns off, and the computer goes to sleep (as I would suspect most people would want; I wish Apple would expose more switches in their Energy Saver system prefs in the first place).

Anyway, it works for me.

Greg Dixon