Microsoft is, at last, expanding Copilot Chat in Outlook so it can work with shared and delegate mailboxes, something that previously limited the AI assistant to a user’s primary inbox. The update means teams managing common mailboxes, assistants handling delegated accounts, and support staff monitoring group inboxes can now use Copilot to summarize messages, draft replies, and analyze email threads directly within those shared mailboxes.
Microsoft is expanding Copilot in Outlook to work directly inside shared and delegated mailboxes. Until now, if you were managing a shared inbox, say, support@company.com or your boss’s mailbox, you had to jump back to your own primary mailbox to use Copilot. That limitation is going away.
This update matters if you:
- Manage a shared mailbox (like a support desk, HR inbox, or finance queue)
- Work as an assistant with delegate access to someone else’s mailbox
- Are licensed for Microsoft 365 Copilot
This is a bug fix that Microsoft is calling a new feature. Shared and delegated mailboxes are how a huge chunk of real teamwork happens in Outlook, executive assistants, helpdesks, finance teams, and HR all live in them. Forcing those users to leave the shared mailbox just to use Copilot was an obvious omission.
If your organization hasn’t paid for Microsoft 365 Copilot licenses, this update doesn’t mean anything for you.
What’s Changing
When you’re working inside a shared or delegated mailbox, Copilot Chat will now be available right there, no need to switch back to your own mailbox first.
Practically speaking, that means:
- Summarize works on emails in the shared mailbox
- Draft can compose replies grounded in that mailbox’s context
- Copilot Chat responds as if the shared mailbox is your own, you don’t need to add phrases like “in support@company.com” to your prompts
- Both full-access shared mailboxes and folder-level delegated permissions are supported
That last point is significant. You don’t need full access to a mailbox to benefit. If you have permission to a specific folder, Copilot can work there too.
Copilot conversation history is saved to your personal primary account, not to the shared mailbox. This means two people who both manage the same shared inbox won’t see each other’s Copilot conversations. Each person’s chat history stays private to them.
This is the sensible design — but it’s worth communicating to your team so nobody assumes Copilot conversations in a shared mailbox are visible to colleagues.
When Is This Rolling Out?
Targeted Release: Begins early April 2026, expected to complete early May 2026.
General Availability: Begins early May 2026, expected to complete early June 2026.
Targeted Release means organizations that have opted into Microsoft’s early-update program. General Availability means everyone else.
What You Need to Do
Nothing, to enable it. The feature arrives automatically for licensed users.
That said, it’s worth doing a quick housekeeping check:
- Review shared mailbox permissions — particularly folder-level permissions — to make sure they still reflect who should have access. Copilot now respects those permissions, so any over-provisioned access might be a problem.
- Tell your team that Copilot history stays with their own account, not the shared mailbox.
- Update any internal training materials that describe how Copilot works in Outlook.
See MC1246031 | Microsoft 365 Roadmap ID 554936
