Moving business email requires more than changing MX records. First measure the data, prepare the destination, copy and verify existing mail, then direct new mail to the new provider. Keep the old service available until verification is complete.
Measure the actual migration
List every mailbox, its used storage, aliases, forwarding rules and shared addresses. Include locally stored POP mail, archives, calendars and contacts. Compare the mailbox-level totals with the hosting dashboard and resolve discrepancies before choosing a plan.
For example, an organisation with 50 users and 120 GB of existing mail will not fit into a plan with 50 mailboxes and a 50 GB total storage pool. “Unlimited” in an old plan name is not evidence that a new service can hold the data or that the old service has no fair-use limits.
Agree scope and preserve a recovery copy
Ask which data types the migration method handles, what work is charged, how access is shared securely and who approves completion. An IMAP mail copy does not automatically move calendars, contacts, signatures or app settings. Keep independent exports of important data and confirm how they can be restored.
Prepare and perform an initial copy
Create the destination accounts with adequate quotas and confirm the target domain is accepted. Test access with one authorised mailbox before migrating the organisation. Use an agreed secure migration method; do not email a spreadsheet of passwords or disable account protections casually.
Compare folder structures, message counts, representative old and recent messages and attachments. Counts can vary because systems handle folders and labels differently, so investigate discrepancies rather than relying on one total.
Cut over incoming and outgoing mail
Save the DNS zone. Change MX records only when the destination is ready, and update SPF, DKIM and DMARC for the services actually sending mail. Preserve website records. Review mail routing on any server still hosting the website so local delivery does not trap messages on the old system.
Coordinate client-app changes with staff. While old DNS answers remain cached, some mail may still reach the source; plan a final synchronisation and monitor both systems. Test inbound, outbound and reply delivery, aliases, shared addresses and automated messages from business applications.
Complete the handover before cancellation
Agree a verification period, document missing items and obtain the organisation's acceptance. Remove temporary migration access when finished. Cancel the old mail service only after the final copy, delivery tests, retained backups and recovery decision are complete. A careful migration reduces disruption, but zero downtime should not be assumed.
Compare Bulamu Mail capacity or request a Google Workspace quote. For large archives or an uncertain storage report, request a capacity and migration assessment before ordering.
Reviewed 3 October 2026. Provider-specific setup should follow the destination documentation, including Google Workspace mail routing setup or cPanel email authentication.