I just installed the latest update on my new Mac Pro (Late 2013). When the computer rebooted, it was stuck on a black screen. I hear the boot chime, but that the screen is black. I have tried rebooting a few times, tried resetting SMC by leaving the computer unplugged for a while. I tried to reset PRAM, but no matter how long I hold down the button does nothing seems to happen. Same thing with command R, which is Apple recovery. I cannot option booed to my Windows boot camp either. Did anyone else with the new Mac Pro have this problem when installing the latest update? Is my system completely screwed? I don't know how I can boot.