This was hapeening to me with 11.13.1b5, and now again on 11.13.2b1. (I have the impresison that I resolved it last time by running "everything" with Onyx, but no such luck this time around.)
When running the install via App Store.app, and agreeing to restart the computer, the shutdown sequence begins as normal. However, soon after the screen inittiall goes black, a mouse pointer shows up .... one I can move.... and I can get no further. Leaving the machine for hours yields nothing.I can force power-off and reboot, but the install has not completed. I have no idea why this is happening, and certianly no clue how to fix it. Suggestions?
MBP Mid-2014