After restarting a Windows server, it may happen that you'll see a screen with a Windows logo and a spinning circle that will not disappear.
This can usually have one of two causes: Windows updates are being installed, or a file integrity check is being formed. The latter usually happens when your server has rebooted unexpectedly (without graceful reboot).
A reboot in this manner, especially with a file integry check can take up to several hours before it's completed, depending on the size of the disk.
