What should I include when migrating email from a server?
Email migration includes mailbox data, addresses, delivery routes and client access. Changing an MX record redirects future delivery; it does not copy existing messages. The migration tool determines which additional items, such as contacts and calendars, can move.
Before you start
- Authorised access to the old and new mail systems, domain DNS and an inventory of users and shared addresses.
Instructions
1. Inventory mail data and features
List mailboxes, aliases, forwarding rules, shared mailboxes, quotas, archives and application senders. Record contacts, calendars and delegates separately. Microsoft’s IMAP migration guidance, for example, states that the IMAP method does not migrate contacts, calendar items or tasks; confirm the limits of your chosen tool.
2. Prepare identities and delivery policy
Create the required destinations using the platform’s supported process and confirm authentication and certificates. Plan MX, SPF, DKIM and DMARC changes with the domain owner. Include reverse DNS and outbound delivery requirements if the new server sends mail directly, without assuming mail reputation transfers with the data.
3. Coordinate final sync and client change
Perform an approved migration rehearsal, compare message counts and sample folders, then plan the final synchronisation and MX change. Keep the old service available for the agreed overlap and account for messages arriving there during cached DNS use. Test inbound, outbound, internal and application-generated mail.
Check the result
- Required mailbox content and separately scoped collaboration data are present.
- Delivery and client sign-in work for the intended addresses after the transition.
Troubleshooting
- New mail arrives but older mail is missing
- Check migration scope, failed folders, date or size limits and final-sync status. An MX update cannot recover mailbox content that was never copied.
Official references
Use the documentation for your installed version when a flag, service name or platform feature differs.