Windows 10 Fast Startup Fast startup (aka: hiberboot, hybrid boot, or hybrid shutdown) is turned on by default in Windows 10 and is a setting that helps your PC start up faster after shutdown. Windows accomplishes 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 actually restarting al