I've got a booting issue on anything that has an external display (HDMI) attached to it.
Both the MBP 2011 and Mini 2012, when anything is plugged into the Thunderbolt -> HDMI (the one from Apple Store) or if anything is plugged into the Mini when I boot, it just hangs on the 'grey screen with the spinning wheel' which eventually stoops spinning.
When I booted in verbose, it rants through the usual as normal, but eventually winds up with a blinking cursor (once a minute it blinks) in the top left hand corner of the external displays.
When I unplug the display on:
MBP: Boots fine. When I connect the display, works fine.
Mini: Boots fine as 2 mins later when I plug it in the TV sees the HDMI signal right away.
Looking at the console logs, I noticed that the WindowServer crashes when something is plugged in externally :-/
This is what I get:
Nice :-/ Free new bug with DP4 xD
Plus i'm having mail.app issues like everyone else...
I'm rolling back to DP3 on my dev machines
Same thing happening to me, except that's what my primary monitor is doing...really hope this gets fixed in DP5...