Sorry for the wordy title, but my problem is thus:

  • When I'm at my desk, I would like to use only the external display.
  • With the nifty gestures in Lion, I have decided I would like to use the internal trackpad on my MacBook
  • To physically touch the trackpad, the lid on my MacBook Pro needs to be open

This used to be a piece of cake with Snow Leopard and below - you plug in the external display, close the lid, plug in a USB device or press a key on a connected keyboard to wake the machine, and once it's woken up and using the external display reopen the lid and the internal screen stays off.

Unfortunately, Lion detects when my MacBook Pro is open and thinks its being helpful by activating the display. Is there a way to disable that? Is there a way to fool Lion into thinking my lid is closed?

  • 1
    Why don't you want the extra screen real estate provided by the internal display? – CajunLuke Aug 7 '11 at 5:38
  • 3
    @CajunLuke It just doesn't work very well. Multiple displays are best when they're sitting next to one another and are the same distance from your eyes. They're also best when two adjacent displays have the same physical dimension and resolution along the shared edge. With my MacBook Pro neither is the case, and I find it annoying having to manage it, and it's frustrating when my pointer disappears to the other screen – Kyle Cronin Aug 7 '11 at 5:54
  • 1
    Others have also wanted this for better heat dissipation as well as WiFi antenna reception. A vertical stand can help there, but it's something that might enhance Kyle's desire to control the screen independent of the display proximity sensor. (that and not needing to buy or place a magic trackpad on his work surface) – bmike Aug 8 '11 at 17:12
up vote 16 down vote accepted

Mac OS X Hints has discovered a command that will allow this:

To go back to pre-Lion behaviour enter the following command in Terminal:

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

To undo this change type type the following command or zap the PRAM (press Cmd+Opt+p+r at power up):

sudo nvram -d boot-args 
  • 4
    Worth noting: you need to restart your computer before this will work. – Damien Wilson Jan 23 '12 at 4:36

I've taken up olivier's suggestion to arrange my monitors to eliminate a common border:

enter image description here

I chose the bottom right because I keep my dock on the left hand side of my screen, and I use my upper right as a hot corner to sleep the display. I also moved the menu bar to my desktop monitor and the MacBook screen is completely dimmed.

There was another option I heard about: using a magnet to make your MacBook think that the lid was closed. This does work - I placed a snippet of a refrigerator magnet near the bottom left side of my keyboard and sure enough my MacBook thought I had closed the display. Unfortunately, Mac OS X also disables keyboard and trackpad input when it thinks the display is closed, so this option didn't work for me.

  • Do you know how to make the external screen the default so windows don't keep popping up on the laptop screen? – Szabolcs Aug 16 at 14:24
  • 1
    Never mind, I searched for the wrong keywords. You just need to drag the white menu bar. – Szabolcs Aug 16 at 14:26

I know this is a bit of a kludge, but my work around for this issue is to hold down the brightness control on my macbook until the screen goes dark.

Like you, I prefer to just work on the larger display, and keep typing with my laptop keyboard (with the laptop display open only partially and open just enough the I can use the laptop's keyboard).

Anyway, this solution works for me.

Re: "..and it's frustrating when my pointer disappears to the other screen.. "

I get around that by just clicking on "mirror displays" option in the System Prefs > Displays > Arrangement

Hope this helps.

  • 3
    "Mirror display" won't work if your external display has a better resolution than your internal display. I use the same solution as you (dimming the screen) but I arrange monitors so they have very few common border, in order not to lose my pointer. – olivier Aug 10 '11 at 11:50
  • 1
    Re: "Mirror display", you're right I should have mentioned that my larger external samsung 22" monitor has the exact same 1680x1050 resolution as my 2011 15" MacBook Pro – user1556373 Aug 10 '11 at 13:09

Not sure if this works in Lion but if you have the lid closed and plug in a USB device it'll power up your monitor and then you can open the lid and your external monitor will be on and your lid will be off.

I ran into the same problem a while ago, and here's what I did:

First, I mirrored the displays, as has already been suggested. Soon after doing this, I realized that it was very distracting to have the macbook's lit screen off in the corner of my eye. This required that I kill the brightness on the macbook's screen. But being the lazy guy that I am, I hated having to manually adjust the brightness every time I un/plugged an external monitor. So I wondered if there was a way to automate the process. I found this free app called Control Plane which let's me set "contexts" based on whether certain devices (monitors, hard drives, etc) are plugged in, whether certain wi-fi networks are in range, etc; and based on these contexts, run certain shell scripts. So all I had to do was write an applescript (called killBrightness.scpt) to kill the brightness on the macbook's screen and a shell script to call killBrightness.scpt; and call this shell script in the required context.


tell application "System Preferences" to set current pane to pane "Displays"

tell application "System Events"
    tell process "System Preferences"
        repeat with theWindow in windows
            if title of theWindow as string is "Color LCD" then
                tell tab group 1 of theWindow
                    tell slider 1 of group 2
                        set value to 0
                    end tell
                end tell
            end if
        end repeat
    end tell
end tell

tell application "System Preferences" to quit

The shell script


osascript /path/to/killBrightness.scpt

Since I plug many different monitors into my macbook, I noticed that when one with a different aspect ratio is plugged in, my windows hang off the edge of the screen. The solution to this would be to resize the windows, but that's highly inefficient when you use a ton of apps and windows like I do; also, me being as lazy as I am, didn't like that solution. So, with the help of the nice folks over at Stack Overflow, I was able to come up with this AppleScript (called resizer.scpt) to automagically resize all windows of (almost) all apps (the caveat is that some applications don't use the correct UI framework hooks, so it's quite difficult to resize them):


property blacklist : {"Finder", "Preview", "Console", "AppleScript Editor", "Spotify", "TaskCoach", "Skype", "VirtualBox"}
property buttonApps : {"LyX", "Eclipse"}
property buttonMaps : {{name:"LyX", Button:1, pname:"lyx"}, {name:"Eclipse", Button:2, pname:"eclipse"}, {name:"Spotify", Button:3, pname:"Spotify"}, {name:"TaskCoach", Button:3, pname:"TaskCoach"}}

tell application "Finder" to set theBounds to bounds of window of desktop

tell application "System Events"
    set bids to bundle identifier of processes where background only is false
end tell

repeat with bid in bids
    tell application id bid
        if name is not in blacklist then
            set appName to name as string
            if name is "Terminal" then
                set newBounds to {0, 0, (item 3 of theBounds) - 10, item 4 of theBounds}
                repeat with theWindow in windows
                    if visible of theWindow is true then
                        set bounds of theWindow to newBounds
                    end if
                end repeat
            else if name is not in buttonApps then
                    repeat with theWindow in windows
                        if visible of theWindow is true then
                            set bounds of theWindow to theBounds
                        end if
                    end repeat
                end try
            else if name is in buttonApps then
                -- get the buttonNumber
                repeat with buttonApp in buttonMaps
                    if (name of buttonApp as string) is appName then
                        set theButton to Button of buttonApp
                    end if
                end repeat
                tell application "System Events"
                    repeat with theProcess in (processes where bundle identifier is bid)
                            tell theProcess to tell window 1 to click button theButton
                        end try
                    end repeat
                end tell
            end if
        end if
    end tell
end repeat

Now, all I had to do was write a similar shell script to call resizer.scpt and put that into ControlPlane and I was all set to be lazy all over again!

Hope this helps

PS: I forgot to mention before that all of this was done on my 15 inch MacBook Pro, running Lion

  • I'd add another upvote if it was possible. Thanks! – noamtm Dec 25 '13 at 13:38

Quick WorkAround (Not an actual solution)

Just check the option "Mirror Displays" in Display Preferences. See below screenshot.

Display Preferences - Mirror Displays

Then turn down the Macbook's brightness to zero.

  • There's multiple issues with this. There are benefits to disabling an unused screen, and this approach loses out on them. 1) frees up VRAM, because it doesn't need a screen buffer (particularly a high resolution retina display), 2) it prevents windows from accidentally popping up on there 3) closes the lid automatically moves all laptop screen windows to the external display – Alexander Aug 30 at 1:36

This is a combination of a few of the other posts/comments here into one place. I'm using a MacBook Pro running El Capitan.

Advantages of this method over the terminal commands:

  1. no restart required
  2. no modification of boot-args


  1. plug in and turn on external monitor
  2. go to System Preferences -> Displays -> Arrangement
    • uncheck "mirror displays"
    • drag the white menu bar from the macbook display to the external monitor (reference with screenshots). This makes the external monitor the Primary display.
    • Arrange the blue boxes so that only the corners touch (screenshot provided by Kyle Cronin in posts above). This prevents the mouse from moving between screens.
  3. close the display options and tap the macbook's dimmer key (i.e. F1) until the screen is black.

Undo steps (preserving the arrangement for later):

  1. tap the brighten screen key on MacBook (i.e. F2).
  2. unplug the external monitor.

Undo steps (to change it back to the default if plugged in again):

  1. tap the brighten screen key on MacBook (i.e. F2).
  2. go to System Preferences -> Displays -> Arrangement
    • drag the white menu bar back to the macbook display.
    • drag the blue boxes back into place.
    • check the mirror displays option.
  3. unplug external monitor.
  • A black screen doesn't mean its not used: your system will know its there and renderings are done on your laptop screen too. Actually, when its blakc the only thing that goes off is your backlighting. – belka Mar 23 at 19:55

This is how I achieve this.

  1. Connect You MacBook with the power cable (charger).
  2. Connect with external Keyboard + mouse.
  3. Turn the MacBook lid down.
  4. Now click keyboard buttons.
  5. Now you are using only your external display, your cursor will not go into your other display. There is only one display now.

Once you have hooked up the external monitor, for sometime you do see this extended monitor setup. But if you don't want to use the laptop screen, simply close the lid of the macbook pro and continue working on the larger screen this works. The laptop doesn't go into sleep mode. This is with the Lion release.

  • I believe Kyle was asking how he can do it with the lid open. – Kevin Chen Jan 13 '13 at 18:34

Your Answer

By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.

Not the answer you're looking for? Browse other questions tagged or ask your own question.