How to boot Windows 8/8.1 Into safe mode using F8 key

1. Open Command Prompt as Administrator.
You can open Command Prompt as Administrator on your Pc by pressing Windows Key + X and then selecting Command prompt(Admin).
2. Now type the below command in command prompt and press Enter key.

bcdedit /set {default} bootmenupolicy legacy

3. Now if you entered the command correctly then windows will report you that operation was completed successfully and your system needs restart to apply these changes.So restart your computers and after that you can use F8 key to boot into Safe Mode.You can disable the F8 below steps.

How to Disable F8 Key :

1. Open Command Prompt as Administrator by Pressing Win Key + X and then select Command Prompt(Admin).
2. Now enter the below command in Command Prompt and press Enter Key.

bcdedit /set {default} bootmenupolicy standard

Now your F8 key for booting the system into Safe Mode is disabled.