First I had a lot of problems installing the update. After the first start while preparing the update (light blue screen) the process freezes at 0%. After removing USB- and Bluetooth devices from my vm (hardware-tab) I was able to successfully update to 1803. But now after the login windows freezes after a short while. The mysterious thing is that I can move my mouse but cannot do anything (open start menu, move windows etc). But if I press ctrl+shift+esc (to open the taskmanager) I see that the mouse courser changes shortly to the spinning cursor and back to the default one. So it seems that the system is at least partially reacting. :-/ After that I've tried to do a clean install. The installation was successful but again after first login when windows tries to display a message (e.g. from cortana or first message from one drive or after inserting a dvd to choose the action) the system freezes again like above. When I boot into safe mode this seems to work but in this mode I don't have the mentioned messages. So I would assume that this is maybe some kind of driver problem.