Disabling Outlook Auto-Mapping in Exchange
Auto-Mapping is a feature introduced in Microsoft Exchange Server 2010 SP1. It allows Outlook (2007 SP2 and later) to automatically map any mailbox to which the user has Full Access permissions.
While useful in many scenarios, in environments with multiple shared mailboxes, it can lead to performance issues and sluggish behavior in Outlook.
✅ The Issue
If a user has Full Access to several mailboxes, Outlook will automatically load all of them—without allowing the user to choose which to display.
🎯 The Solution
You can disable auto-mapping when granting permissions using Exchange Management Shell, by including the parameter -AutoMapping $false.
💡 Example command to assign permissions without Auto-Mapping
Add-MailboxPermission -Identity "MailboxName" -User "Username" -AccessRights FullAccess -AutoMapping $false⚠️ This command grants access but prevents Outlook from automatically adding the mailbox.
🔄 Remove and reassign permissions to disable Auto-Mapping
- Remove existing permissions:
Remove-MailboxPermission -Identity "MailboxName" -User "Username" -AccessRights FullAccess- Reassign permissions without Auto-Mapping:
Add-MailboxPermission -Identity "MailboxName" -User "Username" -AccessRights FullAccess -AutoMapping $false
🔍 Script to find permissions with Auto-Mapping enabled
$FixAutoMapping = Get-MailboxPermission -Identity "SharedMailbox" | Where {
$_.AccessRights -eq "FullAccess" -and $_.IsInherited -eq $false
}
🛠 Tip
If Outlook is running slowly or displaying unexpected mailboxes, check for auto-mapped accounts. Disabling auto-mapping can significantly improve performance.
