OS X Video Driver corruption I have a mid-2010 Macbook Pro with 10.9.4.  I've been using it with a Seiki 39" 4K TV as a monitor for about a month now with no problems.  (This is using an UltraAV MDP to HDMI Active Adapter cable.) For the first time yesterday I selected "1080p" as the resolution in Display Preferences to see what it looked like.  Immediately after going to 1080p resolution, the list of resolutions went blank.  I could click (or option-click) on the scaled circle, and there would be a delay of a few seconds, then I'd see a list of resolutions flash up, and then go away.  Based on what I later figured out, I think if I had tried to click one of those selections when they flashed up, I would have gotten out of 1080p mode.  But I did something else, trying to reset the display preferences to a normal state. (I don't remember what exactly)

From then on, the Mac seems to think it's talking to a dumb TV.  It only lets me select 1080p, 720p, and two other resolutions.  Additionally I get a slider for "Underscan" which tells me it thinks it's talking to a TV in some sort of "TV-mode".  I don't see the full set of resolutions going up to 4k that I was seeing before.  Here is what I've tried with no joy:


reinstall jumbo update for 10.9.4 (no help)
updating firmware on the TV
reseting TV to factory standard
logging in as another user (still see 1080p)
Resetting the PRAM
logging in in Safe Mode (this works!)


I'd like to remove/reset/review all the non-user files that are different or new since the base OS was installed (counting updates).

The only other thing I can think of is to reinstall the whole machine.

Any ideas short of that?

Update:
Option-clicking the "Scaled" choice enabled about 10 additional choices, which are all smaller than 1080p.  But still no 4k choices, and I still get a slider for Underscan, so it's still in 1080p mode.

I tried the SwitchResX app, and it might have had a way to help, but I wasn't able to figure out how to do what I wanted.  The normal default operations didn't seem to allow the resolution I wanted.
Try clicking on "Scaled" while holding the ⌥  key.

Regular click:


⌥ + click: