I've recently bough an early 2011 Macbook Pro 15" and have been using it with my existing NEC 2490 display. It essentially works OK but the problem is that whenever the display is initialised, it takes an abnormally long time to come on. The sequence of events is that it powers up, then flashes the desktop for a second, then goes blank saying 'no signal'. After another few seconds it will usually come on again and stay on. But sometimes it gets stuck in a loop where the display keeps flashing on then going into standby. Other times it will come on but the desktop wallpaper will be missing and replaced with grey, and all the icons will be bunched up in a corner somewhere. This happens every time I boot up, come out of display sleep or plug in the monitor cable. I have tried two different Mini DisplayPort to DVI adapters, one genuine Apple and one third party. I have installed the latest EFI firmware (2.3) and Thunderbolt software update (1.1). I have tried using both DVI inputs on the display (one is DVI-I, the other DVI-D). Finally I have tried changing settings on the monitor all to no avail but perhaps I have missed something else? Funnily enough, it works perfectly in Windows 7 using boot camp. So it seems like more of a software than hardware issue. Please help!