When booting or resuming a device running Microsoft Windows 10, such as the FC-5000 or FC-6000 field controllers, the screen may go black as soon as you get to the point of needing to enter a login password. This often happens when a Windows Update is attempting to load and possibly was interrupted.
To resolve the issue, while at the black screen, press Ctrl-Alt-Del on the keyboard (or on the FC-5000 and FC-6000, press the Windows+Power keypad buttons), then the onscreen Power icon, and then Restart.
Performing a proper restart should clear the issue, allowing the Windows Update to complete.