This is weird. Mac Air 2011, Mavericks, DVI-HDMI, LG IPS LED monitor. In the past once in a while the notebook had a problem detecting the external display at once. I had to restart, restart again, and again, plug the cables in and out, again and again, and then suddenly the Air decided to see the monitor. But now, after using the Air and the cable with another external display (TV-screen), it just refuses to detect the LG-screen. The cable/Air is still working fine with the TV, so that's not the issue. Anyone?