Troubleshooting guide
How to fix the problem
Open Windows Security > Virus & threat protection > Manage settings > Real-time protection. If managed by an organization or other antivirus, the settings may be locked.
If the problem persists
If the protection is managed by another antivirus, check its status. If the settings are managed by an organization, contact the administrator; don't try to get around it by changing the registry of politicians.
Request a repair