If any one of these checks fails, you'll get an error that describes the reason for the failure. At this point, you must ...

If any one of these checks fails, you'll get an error that describes the reason for the failure. At this point, you must fix any errors in the CSV file and resubmit it to create a migration batch. After the CSV file is validated, the number of users listed in the CSV file is displayed as the number of mailboxes to migrate.