I try to use an external projector on an mid 2011 iMac running Snow Leopard. The iMac is connected to the projector using a VGA adapter. DVI is out of the question as the beamer supports VGA only.

When I configure the screen resolution using display preferences I always see "Usable resolution 800x600" regardless of the configured resolution. 800x600 is not really useful for me as I need to display detailed information.

The projector is definitely able to display higher resolutions using a Windows Box or a MacBook Pro on either Snow Leopard or Lion.

I even switched to another projector model, this worked for a while. At one point in time things changed and I am limited to 800x600 again.

Any ideas or help would be greatly appreciated

  • Exactly which projector is it?
    – bneely
    Dec 8, 2011 at 22:23

2 Answers 2


It sounds like OS X isn't properly detecting the resolutions your projector can support.

The best workaround would probably be SwitchResX. It's a shareware app (from what I can tell, no functionality restrictions) that allows you to set custom resolutions (and other display options). Set up one that you've confirmed your projector can support and give it a try.

  • I have the same prblem and tried switchresX is pretty buggy app. Crashes other applications like photoshop. Not too mention that you need a degree to get rid of it. Still looking
    – user17435
    Jan 19, 2012 at 15:40

Make sure you try a SMC reset and then reconnect the projector.

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