This article discusses how to remove automapping for shared mailboxes in Microsoft Outlook for Microsoft Office 365.
In Microsoft Outlook 2010 and in Microsoft Office Outlook 2007, Autodiscover automatically maps to any mailbox for which a user has full access permissions. Autodiscover automatically loads all mailboxes for which the user has full access permissions in the following scenarios:
An administrator grants full access permissions for a user to access another user's mailbox.
The user has full access permissions to a shared mailbox.
If the user has many mailboxes to which he or she has full access, this behavior may cause performance issues when Outlook starts. For example, in some organizations, administrators have full access to all users' mailboxes in their organization. If this is the case, Outlook tries to open all mailboxes in the organization.
To disable automapping, use Windows PowerShell to remove full access permissions from the user for the mailbox, and then add back full access permissions to the user. When you add back full access permissions to the user, use the AutoMapping:$false parameter.
To do this, follow these steps:
Connect to Exchange Online by using remote PowerShell. For more info about how to do this, go to the following Microsoft website:
After you run this command, you're prompted to confirm the action:
Confirm Are you sure you want to perform this action? Removing mailbox permission "email@example.com" for user "firstname.lastname@example.org" with access rights 'FullAccess'". [Y] Yes [A] Yes to All [N] No [L] No to All [?] Help (default is "Y"): y
Grant full access permissions back to the user for the mailbox, but don't enable automapping. To do this, at the command prompt, type the following command, and then press Enter: