Fast startup (aka: hiberboot, hybrid boot, or hybrid shutdown) is turned on by default in Windows and is a setting that helps your PC start up faster after shutdown. Even faster than hibernate. Windows does this by saving an image of the Windows kernel and loaded drivers to the hiberfile (C:\hiberfil.sys) upon shutdown so when you start your PC again, Windows simply loads the hiberfile (C:\hiberfil.sys) into memory to resume your PC instead of restarting it.

If you disable hibernate, then it will also disable fast startup.

You must be signed in as an administrator to turn fast startup on or off.

This tutorial will show you how to turn fast startup on or off for all users in Windows 10.