Many users are having the same/similar problems & the solution is to turn off use sign-in info to auto finish setting up device after update or restart in Windows 10.
For Windows 10 (Version 1709), select the Start button, select Settings > Accounts > Sign-in options, then make sure Use my sign in info to automatically finish setting up my device after an update or restart is turned off.
For previous versions of Windows 10, select the Start button, select Settings > Update & security > Window Update > Advanced options, then select the check box next to Use my sign in info to automatically finish setting up my device after an update.
Another potential solution is to remove any USB devices (wireless mouse, keyboard, external hard drive/s) & wait to see if boot continues, if not then to restart with devices still disconnected (if possible).