Windows Defender is turned off by Group Policy
If you receive a Windows Defender Group Policy error which states Windows Defender – This app is turned off by Group Policy then you need to enable it using Group Policy Editor, Settings or Registry. Learn how to do it.
Check if Windows Defender is turned off via Settings
The first option to take here is to check if Windows 10 is turned off via the Settings app. We’ll do this by launching the pressing Windows Key + I to open the Settings app, then navigate to Update & Security. Choose Windows Defender from the menu, then select Open Windows Defender Security Center. Additionally, go to Virus & threat protection, then take the step to Virus & threat protection settings at the bottom. Find Real-time protection and enable it if it hasn’t been enabled before. This should fix everything. If that doesn’t work, then we will have to do something a bit more difficult, so follow closely.
Enable Windows Defender using Group Policy
Fire up the Run dialog by pressing Windows Key + R, and make sure you’ve logged in as an administrator. Type gpedit.msc into the box and travel to: In the right-pane, double-click on Turn off Windows Defender Antivirus. Now from the Properties box which opens up, select Not Configured and then hit OK. Restart your computer to see the final changes. If all works well, then great.
Tweak the Registry to turn on Windows Defender
OK, so the plan here is to press Windows Key + R to launch the Run dialog, then type regedit into the box, and click Enter after. Doing this should launch the Windows 10 Registry Editor. Search for the following key: If you see a DisableAntiSpyware key there, delete it. If you need additional inputs this post on Windows Defender is turned off or not working will help you.