Just updated to 10.12.4 on my 2013 6-core Mac Pro with D700s and 16 GB RAM. I have the 30" Cinema HD monitor, which still works beautifully. It's connected to the MacPro via Apple's Apple Mini DisplayPort to Dual-Link Display Adapter. Since the update, the monitor is only working at 1280 X 800 and not the 2560 X 1600 it's capable of. I've rebooted, reset the NVRAM, held down the option key in the Display System Preference (only reveals the possibility of even lower resolutions). I called AppleCare, and am being told that my monitor is now obsolete and that my choices are to keep using it at half-rez or purchase a new monitor. Anyone else encountered this problem or have suggestions for a solution? The thought of giving up this gorgeous 30" display makes me cringe for a number of reasons!