How to turn off Windows Defender

HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender
DisableAntiSpyware = DWORD (32-bit) 1

Disable Windows Defender Antivirus

To disable Windows Defender Antivirus permanently, use these steps:

1. Open Start.
2. Search for gpedit.msc and click the top result to open the Local Group Policy Editor.
3. Browse the following path:Computer Configuration > Administrative Templates > Windows Components > Windows Defender Antivirus
4. Double-click the Turn off Windows Defender Antivirus policy.Source: Windows Central
5. Select the Enabled option to disable Windows Defender Antivirus.
6. Click the OK button.
7. Restart your device.