We recently migrated most of our users to Office 365, and due to a miscommunication, three users that should have stayed on premises were migrated, converted to the RecipientTypeDetails RemoteUserMailbox, and had their local mailboxes disconnected. Reconnecting their mailboxes failed as they were of the wrong user type: The solution was to remove the Exchange… Continue reading Restoring an accidentally migrated mail user to On-Prem Exchange