browse to Computer Configuration > Administrative Templates > Windows Components > Windows Defender Antivirus. on the right pane of the Local Group Policy Editor window, double-click the Turn off Windows Defender Antivirus policy. select the Enabled option to disable Windows Defender.Why does Windows Defender keep turning off?
The following 3rd party AVs are known to turn off Windows Defender. It is because they have their own defenders. To have 2 defenders running in the same machine will create conflicts, not to mention redundancy. Do you have one of the below installed ? Avast AVG Norton McAfee