Guide Email

How to migrate mailboxes to a new host

The order that keeps mail flowing while mailboxes move to a new host: create accounts, copy messages, then switch MX records.

iFastHosting Support Team Updated 26 August 2026 9 min read Intermediate

Moving email to a new host is really two separate jobs done in the right order: getting the existing mail copied across, and switching the MX records so new mail starts arriving at the new location. Do them in the wrong order, or too far apart, and you either lose track of old mail or miss new mail arriving during the gap.

Moving a website and moving its email are separate tasks

If you are also moving the website itself, migrating a website to new hosting covers that side. Email can move at the same time or on a different schedule entirely, since MX records and the records that point a website are independent of each other.

Step 1: list every mailbox

Write down every address currently in use, including any that are forwarders or shared mailboxes rather than individually checked accounts. This list is your checklist for the rest of the move, and anything left off it is easy to forget once attention shifts to the new host.

Step 2: create matching mailboxes on the new host

Set up each address on the new hosting account's control panel before anything else moves. Use the same addresses as before — changing an address as part of a migration adds an unrelated complication that is better handled separately, once the move itself is finished and stable.

Step 3: copy the existing mail across

With both the old and new mailboxes active at the same time, copy the content over using one of these methods:

A dedicated IMAP migration tool, which several free and paid utilities offer specifically for copying folders and messages between two IMAP accounts.
Manually, through a mail client configured with both accounts added side by side — drag and drop, or copy, messages and folders from the old account to the new one.
Exporting and importing, if your mail client supports exporting a mailbox to a local file and importing it into another account, though this is generally slower for a large mailbox than a direct IMAP transfer.

Do this before switching MX records, not after

Once MX records point at the new host, the old mailbox stops receiving anything new, but its existing content does not move itself — copying still has to happen, and doing it beforehand means there is no rush and no risk of the old account being deleted before the copy is complete.

Step 4: prepare the MX record cutover

A day or so before switching, lower the TTL on the domain's current MX record to something short, such as 300 seconds. This makes the eventual change spread across the internet in minutes rather than hours once you make it — see how long DNS propagation takes for why TTL controls this.

Step 5: switch the MX records

Once mailboxes exist on the new host and old mail has been copied across, update the domain's MX records to point at the new host's mail server, using the hostname shown in the new control panel. New incoming mail starts arriving at the new mailboxes once the change has spread.

Keep the old mailboxes accessible for a short overlap period

Because MX changes spread gradually rather than instantly, some senders may still reach the old server for a short window after the switch. Leaving the old mailboxes in place and reachable, rather than deleting them immediately, catches anything that arrives during that overlap — see keeping email working during a migration for the full approach to minimising this gap.

Step 6: update mail client settings on every device

Once mail is arriving at the new host, update every device and mail app to use the new incoming and outgoing server names — the old ones will no longer work for anything new, even though the mailbox address itself has not changed. See the setup guides for Outlook, iPhone, Android and Apple Mail for the specific steps on each.

Step 7: confirm and clean up

Send test messages to each migrated address and confirm they arrive at the new mailbox.
Check the copied mail is complete and folders transferred correctly.
Once confident nothing further is arriving at the old host, cancel or remove the old mailboxes.

If something is missed

The most common gap is a device or app not updated with the new server settings, which then shows an authentication or connection error rather than simply failing silently — see fixing authentication failed errors if this happens after the move. If new mail genuinely is not arriving at all, check the MX record has actually finished propagating before assuming something else is wrong.

Re-checking SPF, DKIM and DMARC after the move

A new mail host means new sending servers, which means the domain's existing SPF record almost certainly needs updating to include them — an SPF record referencing only the old host's servers will cause mail sent from the new one to fail authentication. Likewise, DKIM needs enabling fresh with the new host, since the signing key is tied to the mail server actually doing the signing rather than carried over automatically. Review SPF, DKIM and DMARC explained as one of the last steps of any migration, not an afterthought once problems appear.

Migrating a large number of mailboxes at once

For a domain with many mailboxes, migrate a small batch first — one or two accounts — and confirm the whole process works end to end before moving everyone else. This catches a setup mistake, such as an incorrect server setting used consistently across every account, while it only affects a couple of mailboxes rather than the entire organisation, and gives you a tested, repeatable process for the accounts that follow.