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Auto-mapping in Outlook is a beneficial feature that automatically connects multiple shared mailboxes with the user account. It works for Exchange Server on-premises and Exchange Online accounts and the user does not require to manually connect with each shared mailbox using Outlook settings.
Basically, the auto-mapping feature is based on two attributes present in Active Directory.
msExchDelegateListLink – This attribute is associated with shared mailbox. It contains the list of all user accounts who have the FullAccess permission for this account.
msExchDelegateListBL – This attribute is associated with user account, and it has the information of mailboxes whose FullAccess is linked with this user account.
Automapping in Outlook helps users to directly access the mailbox rather than manually changing settings or adding a new mailbox. Automapping came into existence with Exchange Server 2010 SP1 and works like:
- The Administrator grants full access to a user to access the mailbox of another user(s).
- The user account gets full permission to access the mailbox (including shared mailboxes).
But the problem arises when your account has permission over several large-sized mailboxes, and every time the Outlook starts, the Autodiscover feature enlists all these mailboxes. It makes Outlook very slow, and if the bandwidth of your connection is also low, then it will be a headache to work smoothly.
The trouble is that you cannot manually delete any mailbox from your Outlook if the automapping feature is in Enabled state. If you remove the mailbox and restart the Outlook, then the mailbox will appear again due to Autodiscover.
Why disable mailbox Auto-Mapping in Exchange?
Exchange administrators often turn off Auto mapping in Exchange mailboxes for the following reasons:
- Minimize OST file size: With Auto mapping feature enabled in Exchange, shared mailbox data is downloaded to the OST cache file stored locally. This can be the reason for oversized OST file size in Outlook, causing slow performance.
- Efficient Bandwidth: Consistent auto-mapping of mailboxes can cause network congestion, which explains why the bandwidth improves when you disable auto-mapping.
- Improved Outlook performance: Disabling Auto-mapping reduces repeated freezing or crashing of Outlook application. This is because Outlook loads all the mailboxes (provided Full Access) each time during startup.
- Simplified permissions: Auto-mapping sends mixed signals to the server, creating confusion in identifying the email address from which the emails are sent. Manually adding mailboxes simplifies the selection of “Send As” and “Send on Behalf” permissions.
- No unwanted updates: Automapping works with Autodiscover, along with msExchDelegateListLink in Active Directory. When you disable or remove Automapping, you stop receiving unwanted updates in your Outlook.
Remove automapping using Exchange Management Shell
For the removal of automapping feature for Exchange mailbox, the manual method requires to remove full access permission to the mailbox and then reattach full access permission. While reattaching the permissions, the parameter for automapping will be changed to false (AutoMapping:$false parameter).
- Remove the full access permission of the user from the mailbox.
- Add back the full access permission level of the user for the mailbox but keep the automapping parameter to false.
To do this, follow the below steps:
- Start Exchange Management Shell and run the following command:
Remove-MailboxPermission -Identity UserMailbox -User UserName -AccessRights FullAccess -InheritanceType All
Example –
Remove-MailboxPermission -Identity Sales -User David -AccessRights FullAccess -InheritanceType All - Run the command:
Add-MailboxPermission -Identity UserMailbox -User UserName -AccessRight FullAccess -Automapping $false
Example –
Add-MailboxPermission -Identity Sales -User David -AccessRight FullAccess -Automapping $false
The command will provide the full access rights of the mailbox Sales to the user David. But the automapping feature is false. So, Outlook will not automatically add it.
Notes:
- The command will work on Exchange Server 2010 SP2 and later versions.
- The command will remove the reference of the mailbox from the msExchDelegateListLink attribute.
You need to run the command for each user account to remove the automapping. But if the number of a user account is too much and the number of mapped mailboxes is too high, then you should run a command (the command is for removing permissions from a shared mailbox):
$FixAutoMapping | Remove-MailboxPermission
$FixAutoMapping | ForEach {Add-MailboxPermission -Identity $_.Identity -User $_.User -AccessRights:FullAccess -AutoMapping $false}
Important points related to automapping
- Automapping is enabled by default when Full Access Permissions are provided to a user via Add-MailboxPermission. If you need to disable it yourself, then you can do it by keeping:
Automapping: $false - You cannot view the state of the automapping setting for the mailbox (even if it is in enabled/disabled state).
- Automapping feature will work only for the individual user accounts. If you want to apply the auto mapping for a mail-enabled group member, then it will not work.
Conclusion
Auto mapping is a handy feature to reduce the time in including the mailbox to Outlook, when the user has full access permission. But when you migrate Exchange data to Office 365 or upgrade it to a newer Exchange version, you need full access permissions in the new environment. With Kernel Migration for Exchange, you can access the mailbox data from Exchange Server and migrate it to another Exchange Server with the mailbox permissions. The good thing about Exchange Migration tool is that all the properties of mailbox remain the same as the original, after the migration.
Frequently Asked Questions
Ans. Follow the steps mentioned ahead to remove Automapping:
1. Connect your Office 365 email or Exchange Server with the Exchange PowerShell.
2. Remove permissions assigned to the user from the shared mailbox.
3. Remove the shared mailbox from your Outlook account.
4. Disable Office 365 auto-mapping and restore mailbox permissions.
5. Add the shared mailbox as an independent mailbox with its email address.
Ans. To check if Automapping is enabled, run the following command in PowerShell:
Get-Mailbox -Identity “SharedMailboxAlias” | % { Get-ADUser -Identity $_.distinguishedname -Properties msExchDelegateListLink }
If the distinguished name (DN) is mentioned in the msExchDelegateListLink property, automapping is authorized.
