After successfully updating to Sierra today, I then updated iTunes. When re-starting , there was no progress beyond the Bios entry screen. Nor can I can't enter Bios. I've also tried booting from my original Yosemite installation USB with no success (in safe mode or otherwise).
Currently I have disconnected all peripherals except Dell display via DisplayPort and an Apple USB keyboard.
Up until now I've had no issues with my year old Customac
Currently I have disconnected all peripherals except Dell display via DisplayPort and an Apple USB keyboard.
Up until now I've had no issues with my year old Customac