When Microsoft designed Windows 8/8.1 they optimized the boot process in order to make Windows boot (load) faster.
While this was a welcome change from previous Windows versions, the faster boot time made it impossible to use the F8 key to load the Boot Menu for booting into Safe Mode.
Here’s how:
1 – Press the Windows+X key combination to open the Power User Tasks Menu.
2 – Click on Command Prompt (Admin).
3 – Type the following line at the command prompt and then press the Enter key:
bcdedit /set {default} bootmenupolicy
If you entered the above line correctly you should see this message: “The operation completed successfully.” If not, repeat step 3 by copying and pasting the text at the command prompt.
4 – Once you see the “completed successfully” message, restart your PC. You should now be able to boot into Safe Mode by pressing F8 on your Windows 8 computer!