Symptoms
You receive the following message in Microsoft Defender for Endpoint on your Mac:
Real-time protection could not be turned on. Contact your administrator.
Cause
Apple requires that all new system extensions being installed from third-party developers in macOS be manually allowed.
Resolution
2) Click Security & Privacy.
3) In the bottom left-hand corner, click the lock icon.
4) Authenticate using Touch ID or the username and password of an administrator on your Mac.
5) In the left-hand pane, ensure that Full Disk Access is chosen. Then, check the boxes next to the following:
- Microsoft Defender ATP.app
- Microsoft Defender ATP Endpoint Security Extension
6) Close System Preferences.
Outcome
Microsoft Defender for Endpoint will function as expected on your Mac.