Cannot Disable 'Ultra Fast Boot' On BIOS
Solution 1:
- For full boot process, first do a full shutdown... Windows performs a hybrid shutdown by default. One way to force immediate, full shutdown is to enter this in the CMD prompt or just the Run line (Win+(R):
shutdown -s -f -t 00
After the shutdown, before powering up, hold the key(s) (e.g. Del or more likely (F2) to enter BIOS and keep them pressed while pressing and releasing the power button. Newer computers boot so quickly that there may not be time to press the keys, otherwise.
On Windows 8 and later versions, two or three (purposely) aborted boots can force the computer to give more boot options, such as Safe Mode or BIOS.