A Conditional Access policy that required an app protection policy nobody deployed in Intune blocked mobile users on day one. For security architects and CISOs: a 7-layer dependency model for Microsoft 365 tenant security, Cloud Harbor Consulting's 5-step build sequence for Entra ID, Intune, Conditional Access, Purview, and Defender XDR, and the verification step that closes gaps like this before they ship.

Onboarding a device to Microsoft Defender for Endpoint turns on the sensor that sends telemetry. It does not turn on the controls that stop an attack. A device can report "healthy" while nothing blocks files on disk. For the engineers who run MDE rollouts and the leaders who fund them: the five gaps that leave a finished onboarding exposed, and the post-onboarding checklist that closes them.