I have a Macbook Pro (retina) and, using a HDMI cable, I plugged it into a Dell U2711. Mountain Lion suddenly changes the screen display on the Macbook, but nothing happens on the Dell. It's just a black screen that says nothing is connected to it.
But clearly the Macbook sees it. When I unplug it, the screen display reverts to the original version.
What am I doing wrong?
But clearly the Macbook sees it. When I unplug it, the screen display reverts to the original version.
What am I doing wrong?