You can also copy and paste that address into the Registry's address bar. Head to HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender.If User Account Control asks for permission, click Yes. Do note that editing Registry can be risky, so proceed at your own risk. This method works for those running Windows 10 Home.
How to turn off Windows Defender permanently via Registry
In this guide, we will describe how to turn off Windows Defender. Disabling Windows Defender can open your computer to threats, but if you must do so for some reason, here's how you can go about it on Windows 10, Windows 8.1, Windows 7, and Windows XP. Windows Defender is also smart enough to disable itself when you install a compatible third-party anti-virus, but Microsoft doesn't make it easy to turn it off permanently on your own. It's fairly decent in keeping your computer safe from various security threats, though it doesn't hold up to other free and paid alternatives out there. Though it used to be optional with earlier versions such as Windows XP and Windows 7, the anti-malware and the anti-virus protection suite Windows Defender now comes pre-installed with the latest, Windows 10.