How to Remove Mailbox Auto-Mapping in Outlook

Exchange 2010 Service Pack 1 (SP1) and later and Office 365 include a feature that allows Outlook clients to automatically map to any mailbox to which a user has Full Access permissions. If a user is granted Full Access permissions to another user's mailbox or to a shared mailbox, Outlook automatically loads all mailboxes to which the user has full access.

There may be times when you don't want to enable auto-mapping for a mailbox.

TechNet article, Disable Outlook Auto-Mapping with Full Access Mailboxes, explains how to disable auto-mapping behavior for mailboxes as you configure Full Access using PowerShell, but this doesn't help if you configure it from the Exchange Admin Console (EAC). If you or another admin configure Full Access to a mailbox using the EAC, there is no option to disable auto-mapping.

I've seen guidance saying that to remove auto-mapping you must remove Full Access from the mailbox account and re-add it again using the PowerShell method listed in the article above. But I found a better way -- simply run the same PowerShell command against the same mailbox with the -Automapping $false switch.

For example, say Keith Johnson has been granted Full Access to John Smith's mailbox and auto-mapping has been enabled (the default behavior). If you want to remove auto-mapping of John's mailbox in Keith's Outlook, do the following:

• Open the Exchange Management Shell (EMS) or connect to Exchange Online using the Windows Azure Active Directory Module for Windows PowerShell and run the following cmdlet:

Add-MailboxPermission -Identity "John Smith" -User "Keith Johnson" -AccessRight FullAccess -Automapping $false

This command will remove auto-mapping of the mailbox in Outlook, but will not affect any other Full Access permissions. Outlook will automatically remove the full access mailbox from the list of mailboxes on the next Autodiscover refresh cycle.