Stellar Knowledge Base
You may receive an Automap error while exporting mailboxes to Office 365 by using Stellar Repair for Exchange or Stellar Converter for EDB software. The error can occur due to Admin Rights Issue and when Automapping is set to False.
Also, even if we provide Admin rights to any user with Automapping False, the user will not be visible via Configured Outlook Admin profile. In such a case, the users will fail to export the data.
Apply following solution to fix the issue and export mailboxes to Office 365,
You can provide the Admin rights to the user(s) by using Powershell commands. For example, to add full access permissions for an administrator to John Smith's mailbox, type the following command, and then press Enter,
Add-MailboxPermission -Identity email@example.com -User firstname.lastname@example.org -AccessRights FullAccess -AutoMapping $true
Once done you need to configure the outlook profile again with office 365 admin account. Which will then start showing all the delegated mailboxes in the outlook profile. Now, you can start exporting the mailbox data to Office 365 mailbox.