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I have an external monitor (specifically, an HDTV) hooked up to my 2.53GHz 13" macbook pro. This display works fine and I use it with my mac in clamshell mode (eg. with an external keyboard/mouse and the laptop closed and the built-in mac screen turned off)
My Mac has multiple users on it. For User A I can use the mac with the external monitor in both clamshell and dual-monitor setups.
For User B, I can use the monitor in a dual-monitor setup, but whenever I switch to clamshell mode the Mac switches to an incorrect output resolution or frequency setting that my HDTV doesn't recognize, resulting in a blank screen and a message about Unsupported Resolution.
Chances are I did this to myself by misconfiguring my display settings at some point in the past, but I have no idea how to undo it. I (obviously) can't seen the display to change the settings when it's borked. I can see the display settings if I switch to Dual-monitor mode, but those settings only affect the dual monitor setup; no matter how I change the settings in dual-monitor mode, the clamshell mode setup remains borked.
How can I dig myself out of this hole?
Good answer. Unfortunately, deleting that file and rebooting didn't fix the problem. The configuration for User A works fine, but the settings for User B in clamshell mode are still wrong. – emmby – 2010-08-06T13:12:08.247
I've edited to add a few more prefs you can delete. Also be sure that System Preferences is closed when you're removing these files; it might re-create them otherwise. – andyvn22 – 2010-08-06T15:09:58.187
1FWIW, (gobbledegook) is the MAC address of en0 by default. – Chealion – 2010-08-06T19:35:01.997
You did it! The gobbledegook user pref file was the one that was screwed up. Thanks! – emmby – 2010-08-16T16:29:41.783
It's a ByHost preference. They are used for roaming across different Macs when you have a shared network profile. Settings specific to the host you are on go in there. The code that appears there is a UUID of some kind for the machine in question. If you've migrated Macs, you can delete the ones from your old computer without any harm. – CyberSkull – 2014-06-03T09:37:37.700
Hmm, this isn't working in 10.9. – CyberSkull – 2014-06-03T10:31:25.757