Windows Fast Startup feature was first introduced in Windows 8 to make your system boot up faster than the normal booting process by saving the current state of the kernel, a few other processes, and drivers into the disk. But that has some adverse issues when you really want to boot up in a clean environment.
If you are in a need to turn off the Fast Startup feature on Windows 8, Windows 8.1, Windows 10, or Windows 11, here is the step-by-step process to guide you.