10.8.3: Color profile goes wonky w/dedicated GPU

Just upgraded my 2011 MBP to 10.8.3 (combo updater), and having a weird problem: whenever the system switches from integrated to dedicated GPU, the color shifts significantly (I'm using a hardware-calibrated profile, and the color goes extremely cool).

It's not that it's switching profiles on me; the pref pane and ColorSync Utility both show the correct profile selected, and if (while on the dedicated GPU) I switch profiles, they all look funky--very, very cool. It does appear to be responding slightly to different profiles, so it's not just stuck on the wrong profile, either.

Trying a quick manual calibration with the GPU running produced a semi-workable profile, but as soon as it switches back to integrated graphics that profile is so far out of whack the screen is almost unviewable.

Did a "verify profile" with ColorSync Utility, which did show a bunch of minor errors (none of which had been a problem under 10.8.2 or any previous OS), but doing a Repair fixed all of them, and didn't help.

I'm assuming nobody else is seeing this, or there would be a bunch of complaints--but it has to be a software issue, since everything was fine an hour ago. Any suggestions about what I should mess with?

Well, there may or may not be problems with ColorSync in 10.8, but after deleting the ColorSync cache and user prefs, then rebooting, my issue was fixed. (The reboot was necessary--deleting the files alone didn't fix it.)

And honestly, that's the only ColorSync issue I've had so far with 10.8.

The cache isn't easy to get to manually; the easiest way to delete it is to download Onyx and check the box for ColorSync cache.

This Cnet article is for a different problem, but it describes the necessary terminal commands, if you want to do it manually. Short form, this terminal command should do it:


...but I'd probably still use Onyx to be safe.

Note that I didn't do a reboot between deleting the cache and deleting the user prefs, so it's possible that it was actually the prefs that did it; if you delete your cache and reboot, and it's still not fixed, go into your user ~/Library folder and find the two or three prefs with ColorSync in the name and delete those as well, then reboot again. The only thing it might screw up is you'd need to re-select your profile in the prefs pane.