This problem just started last week. When I start the computer, either by restart or a cold boot, it takes 15 seconds before I hear the chime, and then it takes another 45 seconds before the grey screen comes up. From that point everything continues as normal, but this hang happens every single time now. What is really frustrating is when I restart to boot into Windows, this hang causes my bluetooth keyboard to turn off, and it doesn't turn back on fast enough for the option key to bring up the boot menu. So, I have my usb keyboard plugged in now so that I can restart into bootcamp. Any ideas? The most recent change was adding my OWC SSD to my Mac Pro, but that was a week before this issue started. This issue just started a week ago.