For some reason, the video mode gets stuck (ex: 640 x 480 only) and you can't change it - here's how to fix it:
The info is stored in several files:
- /Library/Preferences/.GlobalPreferences.plist
- /Library/Preferences/com.apple.windowserver.plist
- /Users/⟨short-name⟩/Library/Preferences/ByHost/.GlobalPreferences.⟨MAC-addr⟩.plist
- /Users/⟨short-name⟩/Library/Preferences/ByHost/com.apple.preference.displays.⟨MAC-addr⟩.plist
- /Users/⟨short-name⟩/Library/Preferences/ByHost/com.apple.windowserver.⟨MAC-addr⟩.plist
And there may be some in PRAM though that doesn't seem to be the case on recent systems.
To reset the video mode:
- defaults delete /Library/Preferences/.GlobalPreferences ColorSyncDevices
- defaults delete /Users/⟨short-name⟩/Library/Preferences/ByHost/.GlobalPreferences.⟨MAC-addr⟩ ColorSyncDevices
(Each of the above on its own line; the first requires admin.)
(Simply removing the windowserver plists has never done it for me - even from single-user mode, immediately followed by a restart and PRAM reset (multiple times). And FWIW, those files have still not reappeared on my system; perhaps they're no longer used.)
Why might this happen? It's probably related (at least in my case) to moving a boot volume from one system to another - that has a different video card. Which means this might be of some help for moving from one machine to another (ex: upgrade) or deploying an image to multiple machines.
NB: The above info is from a Mac OS X Server 10.4.11 system, though at least most of this should apply to Mac OS X (Client) as well, and other releases.
