[tohvanah]

So, I had my external monitor working after using the usual fix for mirroring (MirrorDisplays.app to toggle it off)...

Then I kept messing with settings (SwitchResX, Display Maestro). I think the last thing I did was try to use it in Clamshell mode by connecting and external keyboard, and closing the lid. That froze the computer.

Now, whenever I connect the external monitor, the lcd flashes, goes to a blank desktop (nothing on screen), and the external goes to sleep. Disconnecting/reconnecting the external produces no change, and I'm forced to hard reset.

I've tried removing display prefs, as in here. Tried reinstalling 10v extensions via Netbookinstaller. Nothing's working.

Thanks for the help.

[unclemiltie]

you gotta sleep first after every reboot before you plug in the external monitor

[tohvanah]

thanks! so simple, i never heard that before.

[gregpearl]

Thanks so much, unclemiltie! I agree with tohvanah that this solution is not bandied about nearly enough. I hope more lucky folks stumble onto this post...