Set resolution of unattached display in OS X?

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I have an HDTV that I’m hooking up via DVI to HDMI from my Mac mini. In my struggle to eliminate overscan I managed to set the screen resolution to something not supported by the tv. How do I change the resolution without that screen attached?

Specifically my tv says it’s “720p and 1366 x 768 Resolution”. The 720p resolution option in OS X made for a ton of overscan (couldn’t see menubar or dock at all). So I tried something x 768 and managed to shoot myself in the foot with an unsupported resolution. I thought it was okay to experiment since a resolution change times out if you don’t accept it. Apparently that didn’t happen for some reason. I’ve already deleted the in /Library/Preferences as I saw suggested in other places, with no effect.


You can “gather windows” in the Displays preference pane when the non-functioning display is attached, so you can set its properties from the display that works.

If the attached display is your only one and you have access to your user’s files (e.g. second display that works), the preferences are stored in


where [UUID] is, well, a UUID and looks somewhat like 598781DD-929A-5CA7-FFED-EF19A1B625F8.

You can try editing this file using Property List Editor (part of the Apple Developer Tools) (I think the relevant entries are Unmirrored Height and Unmirrored Width, it might be difficult to find the correct list entry from VendorID etc. alone however).

You can also trash or rename it, resetting all screen configuration you may have had.

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