If you received the error “Error: MigrationRecipientNotFoundException: A recipient was not found for “mailboxName”” when migrating a mailbox to Exchange Online (Office 365) then check for the below AD attributes. The error from the Exchange Admin Portal on Office 365: Open the on premises Exchange Management Console and search for the user. You should see the mailbox shows it’s a Linked Mailbox instead of a Remote Mailbox as expected: To rectify this, open AD Attribute Editor and browse to the msExchRecipientTypeDetails attribute. You should see the below: Change the Value of 2 to 1 for msExchRecipientTypeDetails as you need the mailbox to show as a user mailbox on premises before…