I am currently running 2880x1800 resolution on my MacBook Pro retina (using the command setgetscreenres).

Whenever I connect to an external display, my Mac changes to a lower resolution. Is there a way to disable this behavior?

Also I've noticed that sometimes instead of extending the display, it mirrors my display on some external displays. I don't think I will ever use mirror mode, so is there another setting to make all external displays extend?

2 Answers 2


In mirroring mode, both screens need to use the same resolution. The external display probably can't support the huge 2880x1800, so it's lowering yours to match.

In System Preferences > Displays > Arrangement tab, uncheck the mirroring option. Then you should see two separate preferences windows, allowing you to set different resolutions for each display. Note — the Arrangement tab is only visible when you have an external display connected.


  • I think Mac "remembers" my external display and doesn't change my MBP resolution when I plug it in, but when I unplug the HDMI cable, it lowers my MBP resolution. I think when I plug into a new external display, it does mirroring by default. Is there a way to change this too?
    – hobbes3
    May 15, 2013 at 21:57
  • 1
    When you unplug the HDMI display, your laptop resolution should not change. I don't know why that's happening. I'm not sure if there's a way to make extended mode the default, but you can change it quickly with Cmd-F1 (or maybe Cmd-Fn-F1)
    – Elliott
    May 16, 2013 at 1:40
  • As far as I understood, OP is having issue when display is set to extended. I am having the same issue. I use Scaled option on the internal screen, as I need a bit more real estate. When I plug in external screen, the internal default to "Best for display".
    – Dzh
    May 9, 2014 at 20:27

I have this exact problem, and deselecting "mirroring" does not work prevent the primary display from changing to this garish cartoon resolution (aka Best For Display).

It is false that a MacBook Pro that has a screen capable of 2880x1800 cannot handle a second screen. It does it rather well. It can even handle 2 extra full 1080p screens (actually one of my extra screens was better than 1080p) on top of the built in retina screen, all simultaneously, without any sort of slow down while doing normal work (not games).

What makes this process somewhat annoying is that when you are used to working in 2880x1800, you may have your windows arranged a certain way. When the resolution goes down, the window arrangement is ruined (they're all shoved into the upper lefthand corner) and going back to the original higher resolution does not restore placement of all your windows. If it were a matter of merely going into the settings and restoring my original resolution, that would only be a minor nuisance.

I should note that OSX will generally remember not to change your primary display's resolution after you have gone through this process once, once for each physical monitor. I believe the port used must be the same as well.

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