Can't disable Windows Defender via Group Policy or the Registry

I wish to disable Windows Defender on Windows 10 Pro, and I know I have to enable the policy Turn off Windows Defender Antivirus via:

• Computer Configuration > Administrative Templates > Windows Components > Windows Defender Antivirus

This didn't work; Windows Defender, and it's modules, remained active.

• I tried disabling it via the Registry, adding the following key with a value of 1, but received Error while renaming:

  HKLM\SOFTWARE\Policies\Microsoft\Windows Defender\DisableAntiSpyware
  

  I restarted my PC several times, turned it off, unplugged it, all to no avail.

Has Microsoft changed something in the latest release that prevents users from turning Windows Defender off?

Solution 1:

I found the solution. It turns out that Windows Defender is so ingrained within Windows 10 that it comes with its own "anti-tamper" protection.

This does two things: prevents you from creating the registry key in HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender by giving you a generic error message and also renders the group policy change ineffective.

In order to disable this, I had to follow these instructions:

1. Go to Virus & threat protection
2. Click on Manage Settings
3. Turn off Tamper Protection
4. Proceed to enable the group policy Turn off Windows Defender Antivirus in Computer Configuration/Administrative Templates/Windows Components/Windows Defender Antivirus or add the registry key.
5. Restart PC

Solution 2:

Update: After a reboot, realtime protection came back on... So this answer does not work for me. But since it proposes a new method (the registry edit) I'm leaving it here. It could help someone else. Different people seem to have success with different methods.

I also find that updating to 21H1 does not help.

For me, it was very difficult to disable Windows Defender in Windows 10 2004 (20H2). I had disabled tamper protection, but still the group policy setting kept being deleted instantly. To see this, one must restart the group policy editor. Also, realtime protection kept being turned on rather quickly when I disabled it.

I was able to overcome this with this registry setting: https://www.tenforums.com/tutorials/5918-how-turn-off-microsoft-defender-antivirus-windows-10-a.html (Search for "Turn_Off_Windows_Defender_Antivirus.reg").

This makes these changes:

[HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows Defender]
"DisableAntiSpyware"=dword:00000001

So it works like this:

1. Disable off tamper protection using the settings panel
2. Also disable realtime protection
3. Apply the registry change
4. Open group policy editor
5. Go to Computer Configuration\Administrative Templates\Windows Components\Microsoft Defender Antivirus and set `Turn off Microsoft Defender Antivirus" to Enabled (not sure if this is required now)

Another option to try is booting into safe mode in order to make the changes: https://www.alitajran.com/turn-off-windows-defender-in-windows-10-permanently/