I upgraded from the ISO and got pretty far, further than ever before I think: "We're preparing your PC" "Getting a few things ready". After "It's taking longer than expected, but..." the screen became black and nothing happened. After two hours of no hard disk activity I rebooted. Now I'm able to login but after that the screen is black again with the mouse showing but not more happens.
Is there a chance to get it running?
Edit: It's not really stuck, I can still access the Ctrl-Alt-Del screen and reboot and so on.