Purview keeps external email out of Copilot answers
Reviewed by Helen Jones
Microsoft Purview’s preview DLP control can exclude email received from external senders from Microsoft 365 Copilot and Copilot Chat grounding, summaries, and citations. The policy uses the sender domain against the tenant’s accepted domains; it does not inspect the email body and it does not remove a user’s normal Outlook access.
Copilot can be useful for inbox summaries and questions about recent work, but external email is also an untrusted input. An admin who wants Copilot to use only internal Microsoft 365 content previously had fewer controls over that boundary. This preview policy gives teams a narrower choice than turning Copilot off. It can remove external email from the AI context while leaving permitted internal sources available, but it needs Purview permissions, a custom policy, and tenant testing before it becomes a dependable control.
Analysis
In Microsoft Purview, test a custom DLP policy for the Microsoft 365 Copilot and Copilot Chat location using the “Email is received from > External users” condition. Use a controlled external message to check what Copilot excludes before applying it more widely.
Source note
Pulse published by Collab365 Spaces, reviewed by Helen Jones on . Cite as "Purview keeps external email out of Copilot answers", Collab365 Spaces.