A successful email move starts with a complete inventory and a tested destination. Use this checklist with the person responsible for your Microsoft 365 organization. It prepares the work; it does not change your DNS or move any data.
Inventory what must keep working
List each user mailbox, alias, shared address, distribution group and forwarding rule. Record mailbox sizes, local archives, delegated access and applications that send mail, including website forms and scanners. Identify contacts and calendars separately from email: the chosen migration method determines what can be transferred.
Agree on the source account for each destination, the information to retain and who will accept the result. Include people on leave and addresses used only occasionally. A list of active employees alone can miss important mail flows.
Prepare access and the destination
Confirm an authorized administrator can reach the Microsoft 365 organization and the authoritative DNS provider. Check the required licences and create the intended accounts. Microsoft specifies that users and mailboxes should be ready before the MX change.
Arrange multifactor authentication (MFA, also called 2FA) and a tested account-recovery process before the change window. The administrator should use the MFA approach appropriate to the organization, rather than disabling existing protections for convenience. Share credentials through an agreed secure channel, not in a support message.
Test a representative mailbox
Select a pilot that exercises real requirements: old messages, folders, attachments, calendar invitations and any delegated access in scope. Record what transfers, what needs separate handling and what fails. Microsoft's setup planning guide helps distinguish account setup from migration work.
Test sign-in from the browser and the approved desktop or mobile application. Confirm that the user can complete MFA without depending on the mailbox that is being moved.
Agree on the cutover and recovery plan
Record the current DNS values and the approved destination values. Assign one person to make the change and another to verify it. Plan incoming and outgoing mail tests, including an external address, aliases and application senders. Have SPF, DKIM and DMARC checked against all authorized senders as part of the DNS work.
Keep the old service available for the agreed verification period. A DNS rollback does not copy messages already delivered to the new service; decide how those messages would be reconciled. Do not delete source mailboxes as soon as one test succeeds.
Accept the result and define ongoing care
Review migration errors, sample historical content, verify key mail flows and record user acceptance. Document the administrator, support contact and any remaining issues. Specify backup coverage and a restoration test separately from the migration; a working mailbox does not prove recoverability.
Discuss the migration with Nuagerie with the mailbox count, source provider, desired timing and known dependencies. The scope of migration, administration and optional external backup must be agreed for your service.