Mavericks not able to use external display at full resolution I have been several months using my mid-2010 15" MBP connected to a Dell U2711 through a miniDisplayPort-DisplayPort adapter, without any trouble cranking the resolution up in Mountain Lion to it's full 2560x1440.

I have just updated my laptop to Mavericks, and I'm not able to use the full resolution of my monitor anymore. I have done several tests, either with the lid open and closed, or trying to force the discrete GPU through gfxCardStatus

Is anyone experiencing this same behaviour? Anything I could try? Possible workarounds?
Finally I found this. Looks like the default EDID configuration for Dell displays is not quite right.

On that post there's also a ruby script that suposedly generates the right file for your display, but it ended up screwing even more my resolution.

I downloaded the file from the first post, and after copying it to /System/Library/Displays/Overrides and rebooting, my display was showing again its awesome full resolution.
The files are suposedly to correct issues with U2713H and U2713HM, but it worked with my U2711 also.

Hope this helps someone as it helped me.