Email migration.

Email migration is a controlled transfer of information and working relationships. Messages may be the largest collection, but addresses, filters, contacts, calendars, shared access, and recovery dependencies can determine whether the new arrangement is usable. Define the scope explicitly so success means more than seeing a folder fill with imported mail.

The Gmail migration guide develops a staged process with exports, sample imports, and account updates. The Fastmail alternatives checklist adds questions about portability and the whole mailbox arrangement. Apply the relevant steps to your source and destination after checking their current documentation.

Choose examples that expose awkward cases in your data: several labels, older attachments, recurring invitations, and contacts with multiple addresses. Keep a readable source copy and record completed transfer batches. During the transition, observe both incoming and outgoing mail, then retire old arrangements only after the remaining account dependencies and shared workflows have been resolved.