Migrate mailboxes to a new provider
Move mail, folders, contacts and calendars with no gap in delivery.
A mailbox migration copies history into the new provider before the MX record changes, so nothing is lost and there is no quiet period.
How it runs
- Inventory
Every address on the domain, its size, and whether it is a real mailbox, an alias or a forwarder. Aliases do not need licences.
- Create the destination
Mailboxes are created at the new provider with temporary passwords, before anything is switched.
- First sync
Mail, folder structure, contacts and calendars are copied over IMAP or the provider API. Large mailboxes take hours; users keep working in the old one throughout.
- Cut over
The MX record is changed, usually in the evening. New mail starts arriving at the new provider within minutes.
- Delta sync
Anything that arrived in the old mailbox during the switch is copied across afterwards.
What users need to do
- Set the new password at first sign-in.
- Add the account to their phone and desktop client.
- Remove the old account once the delta sync is confirmed, not before.
It costs one more billing cycle and it is the cheapest insurance there is. Cancel once a fortnight has passed with no complaints.