How do I get an app to run in Full Screen mode on OS X Lion on my second monitor? It seems to be stuck on my first monitor, and I'd like to move it.

5 Answers 5


You can switch which monitor is the "Primary" monitor by opening the Displays in Preferences and dragging and dropping the menu bar to your secondary monitor. That should make fullscreen apps use your other monitor.

  • 10
    Would be nice, though, if you could have two fullscreen apps simultaneously that way.
    – Thilo
    Commented Jul 21, 2011 at 7:13
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    As much as this helps, I can hardly call this an answer if this is what Apple expects you to do. Commented Jul 27, 2011 at 23:30

This is an excerpt of Apple's AppKit Release Note for Lion regarding full screen apps & multiple desktops.

Multiple Monitors and Full Screen (New since early 2011 seed)

We have made some simplifying assumptions for Lion Full Screen behavior on multiple monitors. Multiple monitors are treated as a single unit by Spaces, and therefore are also treated as a single unit in Full Screen. This means that all monitors will be dedicated to windows belonging to the full screen application, and there can be only one primary full screen window visible at a time. A secondary monitor is useful for inspector windows.

Secondly, because the menu bar is located on the main monitor, the primary full screen window will be located on the main monitor as well. This allows the menu bar, floating toolbar, and full screen window to maintain their interrelationship on the same monitor.

The full document can be found here:

According to this document, your full screen apps will always be shown on your primary monitor, and there is nothing that can be done about it.

  • 14
    +1 for digging this up. But –1 to Apple. This is a ridiculous rationale. Commented Jul 27, 2011 at 12:09
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    This is Apple's fancy way of saying we weren't capable of making it better, we're still working on it >.< Were're (developers) having all kinds of problems with regards to anything fullscreen TT.TT Commented Jul 27, 2011 at 12:13
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    Oh wow. This is a major workflow breaking "assumption" on Apple's part. Do their employees not use multiple monitors at Apple? Commented Jul 27, 2011 at 23:32
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    It's a horrendous mess on Apple's part; they've effectively destroyed multiple monitor support. Even using a single monitor is sub-standard as you can't have another window over the maximised application, e.g. grab, email, etc. Almost a year on and nothing's been done.
    – GlennG
    Commented May 16, 2012 at 21:53
  • 2
    It looks like Apple is working on this. Their ML release notes state "We now allow a fullscreen window to occupy an external display… Much of the underlying Spaces architecture has changed in 10.8". I think they're working on it, and maybe by 10.9 we'll have each display as an independent full-screen app container. Commented Aug 23, 2012 at 18:26

At present there is no way you can. I filed a bug on this during the developer previews and it was marked as a duplicate and the duplicate is still open. (rdar://9741058 and rdar://8056880 for the Apple folk)

My assumption is that Full Screen mode is designed for single monitor setups and it does work especially well on single small monitor setups (read any MacBook or MacBook Pro).

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    This is a seriously flaw, however, as QuickTime X for example can now ONLY use the primary display as fullscreen. Commented Jul 26, 2011 at 8:28

An upgrade to Mountain Lion will resolve the issue as it finally enables using full screen mode on multiple displays.

You can "take an app full screen on either display. Drag the window to the desired display and click the full-screen button."

  • 3
    You can, but that still leaves your other display sitting there doing nothing but displaying that ersatz-brushed-metal linen background. Commented Aug 23, 2012 at 18:24
  • @FrankSchmitt Yes, it's sad that Apple is providing only the first half to a complete solution. "While I save screen space using the fullscreen mode, I have to give up a whole other monitor with valuable screen real estate."
    – gentmatt
    Commented Sep 20, 2012 at 10:26

I find the easiest way to fix this problem when trying to watch Youtube videos fullscreen on my 47" 1080p TV, was to use Fullscreen Mode in Firefox, as this stays on the 2nd screen. ie Only the Apple supplied software has the annoying fullscreen bug/feature. Hope they fix this

  • 2
    I've found that Google Chrome when using HTML 5 video with YouTube put the video on the main monitor (my laptop screen) when I tried to full screen the video on my HDMI connected TV. In my opinion, videos should /always/ full screen to the second monitor, leaving you still able to work on the first one. This kind of configuration can still be set up in VLC, but that doesn't help YouTube.
    – rjmunro
    Commented Jan 25, 2012 at 10:40

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