Lion booting first time on external monitor - what to do?

Discussion in 'Mac OS X Lion (10.7)' started by -mattias-, Jul 24, 2011.

  1. -mattias- macrumors member

    Dec 11, 2009
    So I just downloaded Lion on my MacBook Pro. I'm using it on an external monitor, as my screen on my MacBook Pro is broken.

    But I restarted my Mac and I get this grey screen. But it's like there's 2 screens; 1 on my MacBook Pro and 2 on my external monitor. When I move the mouse over to the left, it disappears so it seems like the screens are split.

    But the only thing I can see is this totally grey screen (or this grey wallpaper they introduced in the iOS 4 multitasking bar). How does I fix this?
  2. schwei56 macrumors newbie

    Dec 26, 2008
    Lion reset your Display Preferences to a default config, partly because your graphics processor thinks your built-in screen is just fine. Now I’d think that just closing the lid of your MBP would override this, and tell Lion you’re using just the external, but apparently not. (Apple will need to address this very soon.)

    You’ll probably need to boot up your new Lion Install on your MBP in "Target Disk Mode", while it’s connected to another Mac. You’ll also need to connect your external display to that Mac. Then go through your “first Lion boot” process on the borrowed Mac. See:

    Once you’re done personalizing your settings, set your Display Prefs to “Mirror Displays” (which really ought to be the default in Lion, on first boot, Steve!). Then log out, and back in, to see if the setting “sticks” that way. Next, reboot as is, and see if the “Mirror” setting sticks across the reboot to Lion, still booting the borrowed Mac in Target Mode from your MBP HD.

    Now, if that works, Shut Down, disconnect your ext display from the borrowed Mac (which has to be able to boot Lion, btw!), and reconnect it to your MBP. Boot the MBP (with the lid closed!), and see what happens. I think that if you leave “Mirror Displays” on, you will be okay.

    You might try doing this at an Apple Genius appointment, but you’ll have to take the external display along to it, plus you’ll need a FW800 cable for Target Mode. Good Luck!

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