shared mailbox access request in exchange online
Grants access to a shared mailbox in Exchange Online. Covers full access vs send-as, automapping, and the approval needed. Use for shared mailbox requests. Not for user mailbox access (different permissions).
TL;DR
In the Exchange admin center open the shared mailbox > Delegation and add Full Access for reading and Send As for sending. Automapping adds it to Outlook automatically within a few hours. Verify the requester has approval from the mailbox owner before granting.
The error
(Access request; no error.)Steps
- Confirm approval from the shared mailbox owner or the requester's manager. Expected: approved. Shared mailboxes often contain sensitive mail; do not grant on request alone.
- Exchange admin center > Recipients > Shared > the mailbox > Delegation. Expected: delegation page open.
- Add Full Access for members who need to read and manage mail. Expected: granted. Full Access without Send As means replies come from the user's own address.
- Add Send As (or Send on Behalf, per policy) for members who must send as the mailbox. Expected: granted per need. Prefer Send on Behalf when attribution matters.
- Tell the user to restart Outlook or wait for automapping (up to a few hours). Expected: mailbox appears. Verify by having them open it.
When to use
- Shared mailbox access requests
- Team queue mailboxes
When not to use
- Another user's personal mailbox (needs owner consent and often legal review)
- Distribution lists (different object)
Compatibility
- Exchange Online; Exchange admin center or PowerShell
Variants
PowerShell bulk grant
Use Add-MailboxPermission and Add-RecipientPermission for scripted grants.
Automapping not wanted
Disable automapping for users who access many shared mailboxes to avoid Outlook bloat.
Why it happens
Shared mailboxes separate the identity (the mailbox) from the access (delegates). Full Access and Send As are independent permissions, and requests usually need a specific combination.
Edge cases
- Remove access on offboarding; shared mailbox delegates are often forgotten.
- Audit shared mailbox delegates quarterly; they accumulate like all access.
Provenance
Resolved from the public thread: https://vectle.com/posts/pstt35L8-IMHnmvL-Rmyy-8g
Maintainer review
No maintainer verification is recorded for this version.
This records the version a maintainer checked. It does not assert that the version is the latest upstream release.