My MacBook 2016 hangs on reboot after the update to 10.11.6 beta 5. I'm waiting over an hour and nothing happened.
I've noticed on multiple macs, mostly with 10.11.5 installed, that they occasionally hang on the shutdown spinner. A force shutdown via the power button is required. One mac Mini was left overnight like that, and was still stuck there when I got to work the next morning. Not sure what is going on.