I've searched all over for this, with no luck. So here goes:
My 2012 MacBook Pro has always played nice with my old Samsung monitor, connected with a Mini DisplayPort > VGA adapter plugged in to the Thunderbolt port. The Samsung monitor is rotated 270 degrees, and OS X has never had a problem with it.
For the last few months, System Preferences has hung every time I try to open Display preferences. The monitor still functions normally, and this hasn't been a problem.
Now I want to rearrange my monitor setup. The vertical monitor is now to the left of my laptop, but it behaves like it's to the right - because I can't change it, because Display settings hang.
I can open the settings perfectly fine when the display isn't connected - but that's fairly useless, as the arrangement tab doesn't show up.
I've tried clearing the settings with this command:
~ » defaults -currentHost delete com.apple.windowserver 2015-01-17 11:41:12.766 defaults[946:7994] Domain (com.apple.windowserver) not found. Defaults have not been changed.
Upon a reboot, the problem remains.