Microsoft M365 Groups (M365) - Ownerless Group Policy


Introduction

Microsoft 365 Groups (used by Teams, Outlook, Planner, and more) requires at least one owner to manage membership, settings, and lifecycle. When a group becomes ownerless, for example, if the owner leaves the organization, the group risks falling out of security compliance leaving abandoned content that may need to be deleted

Michigan Medicine is enabling an Ownerless Group Policy as part of our ongoing efforts to strengthen data governance and retention practices. This policy automates the process of identifying Microsoft 365 (M365) groups without an active owner, such as a Team created by someone who has since left Michigan Medicine, and notifies remaining active members, giving them the opportunity to assume ownership.

What is an M365 Group?

An M365 group is a collaborative workspace that provides shared access to resources like email, files, and calendars. Groups can be created in several ways, such as when a Microsoft Team is created.

  • The creator of the group becomes the default owner, but additional owners can be added.
  • A group becomes ownerless when no active users are assigned the owner role.

Learn more about Microsoft 365 Groups below in the reference section.

Why is Ownership Important?

Active ownership ensures:

  • Functionality: Owners manage membership and settings.
  • Security: Owners control access and permissions.
  • Lifecycle Management: Ownerless groups are more likely to be deleted during cleanup.

How the Policy Works

  1. Detection: Microsoft 365 identifies groups that have no owners.
  2. Notification: The top 5 most active members receive an email asking them to take ownership.
  3. Assignment: When any notified user accepts, they are added as owner and further notifications stop.
  4. Cleanup: If no owner is assigned within 30 days, the group will be marked for deletion (per our internal lifecycle process).

Tip: Multiple owners are encouraged for continuity and resilience.

How to Avoid Ownerless Groups

To prevent your groups from becoming ownerless:

  • Regularly review your group membership
  • Delete groups you no longer need.
  • Assign multiple owners for redundancy.
  • Before leaving Michigan Medicine, transfer ownership of important groups.

Reference: