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ArjanBroekhuizen's avatar
ArjanBroekhuizen
Iron Contributor
Aug 14, 2025
Solved

Discrepancy with shared mailbox when removing user-mailbox

Hello,

When we remove a mailbox from Exchange 365, we see a discrepancy with the shared mailboxes the user had access/permissions for.
- the user-object is deleted for "Full-Access"
- the user-object is not deleted for "Send As".

Because the user/mailbox does not exist anymore, now the SSID (S-1-5-21-.......) is displayed instead of the users mailaddress.

Why isn't 'Send As' cleaned up; 'Full-Access' is? Now we have several old permissions on the shared mailboxes.

Kind regards,
Arjan

  • This is expected behavior — Full Access is mailbox-level and gets cleaned up automatically, but Send As is an Active Directory permission and isn’t removed when the user is deleted. You’ll need to manually clean up the orphaned Send As entries from the shared mailboxes.

4 Replies

  • Jalessa's avatar
    Jalessa
    Iron Contributor

    This is expected behavior — Full Access is mailbox-level and gets cleaned up automatically, but Send As is an Active Directory permission and isn’t removed when the user is deleted. You’ll need to manually clean up the orphaned Send As entries from the shared mailboxes.

  • Even when there are more users with Full Access permissions, the problem occurs. Ownership is not a problem. It is that the SendAs permission is not removed correctly.

  • tonnLtis's avatar
    tonnLtis
    Copper Contributor

    Before deleting a user's mailbox, first migrate the Full Access permissions of the shared mailbox to another user in the Exchange Admin Center to avoid loss of ownership.

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