How to Migrate Email to a New Provider: Step-by-Step

Moving your email to a new provider feels like it should be a single button. It almost never is. Your mail lives in one company's servers, your new home is another company's servers, and the two were not built to hand a decade of messages back and forth on command. So the move becomes a project: copy the messages without losing any, keep the folders and labels you organized them into, bring along the contacts and calendar that quietly depend on the same account, redirect anything still being sent to the old address, and confirm — actually confirm, not assume — that everything made it across before you let go of the old inbox.

Done carelessly, an email migration loses things in ways you do not notice for months: a folder that did not copy, a year of sent mail that got skipped, a contact list left behind, a recurring invoice that kept landing at an address you stopped checking. Done carefully, it is uneventful — which is the goal. Nobody emails you to say your migration went well; they email you when a message bounced or a thread disappeared. The whole job is to make sure that email never gets sent.

This guide is the complete, practical walkthrough. You will get the full sequence in order — plan, copy, preserve structure, move contacts and calendar, forward, verify, cut over — written as concrete steps you can follow regardless of which providers you are moving between. There is a comparison table of the actual migration methods (built-in importers, IMAP copy, imapsync, and connecting both inboxes in one app) so you can pick the right tool for your situation, worked examples of the verification math that catches a botched copy, and an honest accounting of what does not migrate and what to do about it.

We will keep it plain and method-agnostic. Gmail, Outlook, iCloud, Fastmail, Proton, a custom domain — the mechanics rhyme across all of them because they nearly all speak IMAP underneath. Where a specific provider does something unusual, we will call it out. And near the end we cover the part most guides skip: how to run the move so you never actually lose access to your mail mid-migration — by keeping both the old and new accounts live in one place — and what an AI-native email client does to make that low-risk instead of nerve-wracking.

What does it actually mean to migrate email to a new provider?

Migrating email means copying your existing mail — and the structure around it — from your current provider's servers onto a new provider's servers, then pointing your daily life at the new account. The word "copying" matters: a good migration duplicates your mail to the new home first and only retires the old one once you have verified the copy. You are never moving the only copy of anything; you are creating a second copy and then decommissioning the first.

It helps to separate the four things that ride along with an email address, because they migrate by different mechanisms and people forget the last three. First, the messages themselves — every email in Inbox, Sent, Archive, and your folders. Second, the structure — your folder tree or label set, your read/unread states, your stars and flags. Third, the contacts — your address book, which lives in a separate system (often CardDAV) from your mail. Fourth, the calendar — events and invites, in yet another system (often CalDAV). A migration that copies only the messages and forgets contacts and calendar is the single most common way people arrive at a new provider feeling like half their data vanished.

There is also a fifth thing that does not copy at all and has to be rebuilt: the configuration that was attached to the old account. Filters and rules, the signature, the vacation responder, app passwords and connected services, two-factor settings, and — critically — every external account that uses this email as its login or recovery address. None of that travels with the messages. Recognizing that early is what separates a clean migration from one that drags on for weeks as you discover, one service at a time, what was tied to the old address.

How do you plan an email migration before you move anything?

The temptation is to start copying immediately. Resist it for an hour. The migrations that go wrong are almost always the ones that skipped planning, because email is full of dependencies that are invisible until they break — the bank that texts a code to verify a login change, the domain whose DNS you forgot you control, the "Sent" folder that is three times larger than your inbox. Spend a little time mapping the territory and the actual copy becomes mechanical.

Start by taking an inventory of what you are moving and what depends on it. Then choose your destination deliberately, confirm both providers will let you connect over IMAP (the protocol that makes a clean copy possible), and pick a method that fits your volume and comfort. The steps below are the planning phase in order — none of them move a single message, and all of them prevent a problem later.

1. 1

   Inventory your mailbox and its dependencies

   Note your total mailbox size and message count (your provider shows storage used in settings), and skim your folder tree so you know what "complete" looks like later. Then list everything that uses this email address as a login or recovery address — bank, government, social, shopping, your password manager's account. This list is what you will update after the move; building it now is the difference between a smooth transition and months of surprises.

2. 2

   Choose and provision the new account

   Decide where you are going and create the account before migrating — Gmail, Outlook, iCloud, Fastmail, Proton, or your own domain on a host. If you are moving to a custom domain, set up the domain and its mail records (MX, SPF, DKIM, DMARC) and confirm you can send and receive a test message before you copy years of mail into it. Migrating into a half-configured destination wastes the whole effort.

3. 3

   Confirm IMAP access on both sides

   Almost every clean migration relies on IMAP — the protocol that lets a tool read your folders on the old server and write them to the new one. Enable IMAP in both accounts' settings. Note the exceptions: Gmail and iCloud require an app-specific password when two-factor is on (your normal password will not work for IMAP), and Proton Mail does not expose IMAP directly — it requires Proton Mail Bridge on desktop, which presents a local IMAP endpoint for migration tools to use.

4. 4

   Pick a migration method that fits your volume

   For a few thousand messages, a provider's built-in importer or connecting both accounts in one email app is the simplest path. For a large or business mailbox, or many accounts at once, a dedicated IMAP-to-IMAP copier like imapsync is more reliable and re-runnable. Match the tool to the job — the comparison table later in this guide lays out the trade-offs so you can choose without guessing.

5. 5

   Schedule a low-traffic window and tell key people

   Mail keeps arriving while you migrate, so pick a quieter stretch (a weekend, an evening) to do the bulk copy, and plan to re-sync any messages that arrived during it. If this is a work or shared address, give a heads-up to the handful of people who email you most, and prepare the new-address note you will send once the move is verified — covered in the cut-over section below.

What are the ways to migrate email, and which should you use?

There are four practical methods, and the right one depends on how much mail you have, which providers you are moving between, and how comfortable you are with a terminal. They are not mutually exclusive — a common pattern is to connect both accounts in one app for the day-to-day continuity and run a dedicated copier in the background for the bulk transfer. Here is the honest comparison.

Read the table as a decision aid, not a ranking. A built-in importer is the easiest path when one exists for your exact source-and-destination pair. IMAP copy inside an email client is the most universal because nearly every provider speaks IMAP. imapsync is the most thorough and the most repeatable, which is why it is the standard for large or business migrations, at the cost of using the command line. Connecting both inboxes in one app is less a copy method than a safety net — it keeps you working out of both mailboxes so the move never cuts you off, and it pairs with any of the others.

How do you copy your messages with IMAP step by step?

IMAP is the workhorse of email migration because it represents your mailbox as folders of messages on a server, which means any IMAP-aware tool can read those folders from the old provider and write them to the new one — preserving the messages, their read/unread state, and their flags as it goes. Whether you use a desktop client, a unified email app, or imapsync, the underlying motion is the same: connect to both, then copy folder by folder. Here is the IMAP copy done as a deliberate sequence.

Two principles run through all of it. First, copy, do not move — leave the originals on the old server untouched so it stays a complete fallback until you have verified the new side. Second, go folder by folder and confirm each one rather than selecting everything at once; a per-folder approach makes it obvious if one folder fails, instead of burying a failure inside a giant batch.

1. 1

   Add both accounts over IMAP

   In your email client or migration app, add the old account and the new account, both configured as IMAP (not POP — POP downloads and can delete, which is the opposite of what you want). For Gmail and iCloud, use the app-specific password you generated. For Proton, point the tool at the local IMAP address from Proton Mail Bridge. Confirm both accounts show their full folder trees before copying anything.

2. 2

   Re-create the folder structure on the new account first

   If your tool does not create folders automatically, make the destination folders to match the source — same names, same nesting — so messages land where they belong instead of in one undifferentiated pile. Doing this up front means the copy step just fills folders that already exist, which is faster and far easier to verify.

3. 3

   Copy the Inbox, then Sent, then everything else

   Start with the Inbox, then the Sent folder (people routinely forget Sent and lose every email they ever wrote), then Archive/All Mail, then your custom folders one at a time. Select a folder's messages and copy them to the matching destination folder. For very large folders, copy in batches of a few thousand so a hiccup costs you a batch, not the whole folder.

4. 4

   Use imapsync for large or business mailboxes

   For tens of thousands of messages or multiple accounts, run imapsync instead of dragging by hand: it connects to both servers, mirrors the folder tree, and copies messages with their dates and flags intact. Its best property is being re-runnable — run it once for the bulk, then again later and it copies only what is new, which is exactly how you catch mail that arrived mid-migration.

5. 5

   Re-run the copy to catch newly arrived mail

   Mail keeps coming while you migrate. After the bulk copy, do a second pass (re-run imapsync, or re-copy just the recent Inbox messages) to bring over anything that landed during the transfer. Combined with forwarding — set up next — this is how you reach the point where the new account holds everything and the old one is purely a fallback.

How do you migrate email using a provider's built-in import tool?

Most major providers ship an import tool aimed at exactly this moment — you are arriving at their service and they want your old mail to come with you. These tools are the easiest path when one exists for your specific source-and-destination pair, because they handle the IMAP connection and folder mapping for you behind a friendly screen. The catch is that they only cover certain pairs, the label-versus-folder translation is imperfect, and a few of them quietly cap how much they will pull in one run.

The mechanics differ slightly by provider but the shape is consistent: you authorize access to the old account, the tool reads its folders, and it copies the mail into the new account, usually with a progress indicator and an email when it finishes. Here is how the major importers work and where each one needs care.

1. 1

   Importing into Gmail (Import mail and contacts)

   In Gmail, go to Settings → Accounts and Import → "Import mail and contacts," enter the old address, and authorize. Gmail pulls mail and contacts and keeps importing new mail for about 30 days. It maps incoming folders to labels (Gmail has labels, not folders), so expect your old folder names to become labels — review them afterward and tidy any that did not map cleanly.

2. 2

   Importing into Outlook / Microsoft 365

   Outlook.com can connect another account under Settings → Mail → Sync email, which pulls existing mail and continues syncing. For desktop Outlook, the classic route is adding both accounts and dragging folders, or importing a .pst export of the old mailbox. For a domain on Microsoft 365, admins can run a server-side IMAP migration from the admin center for everyone at once.

3. 3

   Importing into Fastmail

   Fastmail has a strong built-in importer: Settings → Migrate, where it can pull mail, contacts, and calendar from Gmail, Outlook, and other IMAP accounts, preserving your folder structure. It is one of the more complete importers because it deliberately brings the address book and calendar along, not just the messages — which is why Fastmail is a common, low-friction migration destination.

4. 4

   Importing into Proton Mail (Easy Switch)

   Proton's Easy Switch tool imports mail, contacts, and calendars from Gmail, Outlook, Yahoo, and IMAP accounts, mapping folders to Proton's labels/folders. Because Proton encrypts your mailbox, the import happens through Proton's tooling rather than a generic IMAP client. If you later need IMAP access to Proton (for imapsync or another app), that runs through Proton Mail Bridge on desktop.

5. 5

   Verify the import actually finished and completely

   Importers report "done" but can silently skip a folder or stop at a size limit. When the importer says it is finished, do the verification math in the next section — compare message counts per folder between old and new — before you trust it. An importer is convenient, not infallible; treat its completion notice as a claim to check, not a guarantee.

How do you keep your folders, labels, and rules after migrating?

Copying messages is only half of preserving your mailbox. The organization you built — the folder tree, the label colors, the filters that auto-sorted incoming mail, your read/unread states — is what makes the mailbox usable, and it travels unevenly. IMAP carries the folder structure, read/unread, and flags for the messages it copies; it does not carry filters, rules, signatures, or label colors, because those are provider-specific settings, not part of the mail itself.

So plan to preserve structure in two passes: let the copy bring over folders and message states, then manually rebuild the configuration that lives in settings. The steps below cover both, plus the label↔folder translation that trips up anyone moving to or from Gmail.

1. 1

   Preserve the folder tree during the copy

   When you re-create destination folders to match the source (or let a good importer do it), the structure carries over and messages land in the right place. Keep the names identical during migration even if you plan to reorganize later — matching names is what lets you verify counts folder-by-folder. Rename and restructure after you have confirmed everything copied, not during.

2. 2

   Handle the label-versus-folder translation deliberately

   If you are leaving Gmail, decide how its labels become folders: a message labeled both "Clients" and "Invoices" can only live in one folder, so pick the primary label as its folder home. If you are moving to Gmail, your folders become labels automatically. Reviewing this mapping is the difference between an organized new mailbox and a pile of near-duplicate folders.

3. 3

   Rebuild filters and rules from scratch

   Filters do not migrate. Open your old account's filter list, screenshot or note each rule (sender → folder, subject contains → label, etc.), and re-create the important ones in the new provider's rules interface. Most people find they only relied on a handful; rebuild those and let the rest go. Do this before heavy mail starts flowing to the new account so incoming mail sorts itself from day one.

4. 4

   Re-create signatures, vacation responders, and aliases

   Your signature, any auto-reply, and send-as aliases are account settings that stay behind. Copy your signature text over, set up the vacation responder if you use one, and re-add any aliases or "send mail as" addresses in the new account. These are quick but easy to forget until you send a signature-less email to a client.

5. 5

   Spot-check read/unread and flags after copying

   IMAP usually preserves read/unread status and stars/flags, but tools vary. After the copy, open a few folders and confirm that read messages are still read and flagged messages are still flagged. If everything came across as unread (some methods do this), it is cosmetic, not data loss — but better to know before you start triaging thousands of falsely-unread messages.

How do you bring your contacts and calendar to the new provider?

Here is the part that catches people off guard: your contacts and calendar do not migrate with your email, because they are not email. They live in separate systems — contacts in an address book (typically CardDAV), calendar in an events store (typically CalDAV) — that happen to be bundled with your account. Copy only the mail and you will arrive at the new provider with an empty address book and a blank calendar, then spend weeks rebuilding birthdays and recurring meetings by hand. Move them deliberately and it is a five-minute export-and-import.

The universal mechanism is standard file formats: contacts export as a vCard (.vcf) file, calendars export as an iCalendar (.ics) file, and nearly every provider can both produce and ingest these. A few importers (Fastmail's Migrate, Proton's Easy Switch, Gmail's import) will grab contacts and calendar for you — but when in doubt, the export-import path always works. Here is the sequence.

1. 1

   Export contacts as a vCard (.vcf) file

   In your old account's Contacts, choose Export and pick vCard format (Google Contacts: Export → vCard; iCloud: select all → Export vCard; Outlook: Export, then convert if needed). This produces one file containing every contact. Save it somewhere you will find it — this single file is your entire address book, portable to any provider.

2. 2

   Import the vCard into the new account

   In the new provider's Contacts, choose Import and select the .vcf file. All contacts appear in the new address book with names, emails, phone numbers, and notes intact. Spot-check a few entries afterward — occasionally photos or custom fields do not survive the round trip, but the core contact data reliably does.

3. 3

   Export each calendar as an iCalendar (.ics) file

   Calendars export one at a time. In the old account, open each calendar's settings and export it to .ics (Google Calendar: Settings → Import & export → Export; iCloud and others have an equivalent). If you keep several calendars (personal, work, a shared one), export each separately so you can re-create the same separation on the new side.

4. 4

   Import calendars into the new account

   In the new provider's Calendar, import each .ics file into a matching calendar. Past and future events come across, including recurring ones. Note that .ics is a snapshot — if you keep using the old calendar after exporting, those new changes will not appear in the new one, so do the calendar move close to your cut-over and stop adding events to the old calendar afterward.

5. 5

   Reconnect calendar sharing and invites

   Shared calendars and the people you share with do not come through an .ics export — sharing is a relationship between accounts, not data in the file. After importing, re-share any calendars with the right people and check that recurring meeting invites you own still have the correct attendees. This is the last loose end in the contacts-and-calendar move.

How do you migrate email without downtime or losing access?

"Downtime" in an email migration is not a server being offline — it is the window where mail might arrive at an address you have stopped watching, or where you have closed the old account before the new one is proven. Both are avoidable. The goal is a state where, at every moment of the move, you can read and send from your mail and no incoming message can fall into a gap. That is achieved with overlap, not with a clean break: keep both accounts live, forward the old to the new, and only retire the old one once you have verified the new one for weeks.

The single most important habit is to never delete or close the old account until you are certain. Migration is cheap to redo and expensive to undo — if a copy was incomplete, an open old account means you just re-run it; a closed one means the data may be gone. Here is how to run the move with continuous access.

1. 1

   Keep both accounts open and accessible throughout

   Do not close, downgrade, or stop paying for the old account during the migration. Keep it fully accessible so it remains a complete fallback and a re-runnable source. The new account is unproven until you have verified it and lived in it; the old one is your insurance policy for as long as you keep it open.

2. 2

   Connect both inboxes in one place so you never lose sight of either

   Add the old and the new account to the same email app and work out of a single inbox that shows both. This removes the riskiest part of a migration — the period where mail is split between two places and you might miss something in the one you check less. You see every message from both accounts in one view, send from whichever address is right, and the move stops being a leap.

3. 3

   Set up forwarding from the old account to the new

   Turn on automatic forwarding in the old account so anything that still arrives there is delivered to the new address immediately. This catches mail from senders who have not updated your address and from services tied to the old account. Forwarding is the safety net under the cut-over: even if you miss telling someone, their email reaches you.

4. 4

   Run the bulk copy in the background

   With both inboxes connected and forwarding live, run the heavy copy (importer or imapsync) without pressure — you are already receiving and reading all new mail through the connected accounts, so the bulk transfer of old mail can take as long as it needs. There is no moment where you are cut off waiting for it to finish.

5. 5

   Cut over only after verification

   Once counts match (next section) and forwarding is confirmed working, make the new address your primary: update your signature, set the new account as the default "from," and begin telling contacts. Keep the old account open and forwarding for weeks after, so the long tail of infrequent senders and annual services still reaches you while you update them.

How do you verify nothing was lost after migrating?

Verification is the step that turns a hopeful migration into a finished one, and it is the step people skip. The fix is simple arithmetic: compare the message count of each folder on the old account against the matching folder on the new account. If Inbox had 4,212 messages on the old side and shows 4,212 on the new side, that folder copied completely. If it shows 4,180, you are missing 32 messages and you re-run the copy for that folder. Counts do not lie, and they catch the exact failure mode — a partial or skipped folder — that otherwise goes unnoticed for months.

Do the count comparison folder by folder, paying special attention to the big ones (Archive/All Mail) and the easily-forgotten ones (Sent), because those are where copies most often come up short. Most clients show a folder's message count in its properties or next to its name; if not, a search for all messages in the folder returns the total.

Beyond counts, do a few qualitative spot-checks, because a number matching does not prove the messages are intact. Open your oldest email on the new account and confirm it has its original date — some flawed copies stamp every message with the migration date, which scrambles your chronology even though the count is right. Open a message with an attachment and confirm the attachment is actually there and opens. Find a long thread and check it reads in order. Search for a specific old email you remember and confirm it is findable. These four checks — date, attachment, thread, search — catch the subtle corruptions that a count cannot.

Finally, verify the live flow, not just the archive. Send a test email from the new account to an outside address and confirm it arrives and does not land in spam (a new sending domain sometimes does until it builds reputation). Have someone reply so you confirm receiving works. Send a message to your old address and confirm forwarding delivers it to the new one. Only when the archive checks out and the live flow works in both directions is the migration genuinely verified.

What does not migrate, and how do you handle it?

Some things simply do not come across in any migration, and knowing the list up front means you handle them on purpose instead of discovering each gap as a small crisis. None of these are reasons not to migrate — they are just the manual remainder after the mail, contacts, and calendar are copied.

The biggest category is everything that used the old address as its identity. Logins and recovery addresses on external services do not update themselves; you change each one. Two-factor settings tied to the old account, app passwords, and connected third-party apps all stay behind and must be re-established on the new account. Provider-specific configuration — filters, signatures, vacation responders, label colors, themes — is settings data, not mail, so it is rebuilt by hand. And a few provider-proprietary features have no equivalent elsewhere: Gmail's categories (Promotions, Social), some smart-folder logic, and similar conveniences are recreated with the new provider's own tools or simply left behind.

There is also the question of your old address's future. Forwarding handles the transition, but decide your end state: keep the old account open indefinitely as a forwarder (the safest, if you can), or eventually close it once nothing important still arrives. If the old address is on a custom domain you control, you can keep receiving at it forever by pointing it at the new mailbox. If it is on a free provider you are leaving, plan to keep it open in a reduced state for a long tail — annual renewals, tax documents, and that one service you forgot all surface over a full year.

How does AI Emaily make migrating to a new provider low-risk?

Here is what makes a migration stressful: the in-between. For days or weeks your mail is split across two accounts, and the anxiety is not the copying — it is the fear of missing something in the inbox you are checking less, or of cutting over before you are sure. The copy is mechanical; the continuity is the hard part. That is exactly the gap AI Emaily is built to close.

AI Emaily is an AI-native email client that connects every account you have — Gmail, Outlook, iCloud, Fastmail, Proton (via Bridge), and any IMAP provider — into one inbox. During a migration, that means you connect both the old and the new account and work out of a single view that shows mail from both. You never lose access to either side, you never have to remember which inbox a message arrived in, and you send from whichever address is correct without switching apps. The riskiest part of the move — the overlap window — becomes a non-event, because both mailboxes are simply there in front of you the whole time.

That continuity is what makes the rest of the move low-stakes. You run your bulk copy (importer or imapsync) in the background without pressure, because you are already receiving and reading all new mail through the connected accounts. You set up forwarding from the old account and watch it land in the same unified inbox. You verify the new account's folders against the old ones, knowing both are live in one place. And when you cut over, you do it on your schedule — keeping the old account connected and forwarding for as long as you want a safety net, then quietly disconnecting it once nothing important still arrives. Nothing forces a clean break before you are ready.

It is private by design — your mail is yours, used to help you work, not to train models for anyone else — which matters when you are connecting two full mailboxes at once. And you stay in control throughout: in its default Copilot mode, AI Emaily drafts and organizes but waits for your approval before anything sends, so connecting your old and new accounts during a migration never means handing over the wheel. You can start free at app.aiemaily.com/signup: the Free plan is $0 and connects your inboxes with AI drafting, and Pro is $17.99/month billed annually when you want it across everything. The point is not that the app copies your mail for you — your importer or imapsync still does the heavy transfer — it is that you never lose sight of either inbox while it happens, which is the difference between a migration you dread and one you barely notice.

The bottom line on migrating email to a new provider

Migrating email is a project, not a button, but it is a well-understood project with a fixed order. Plan first: inventory your mail and everything that depends on the old address, provision the new account, and confirm IMAP works on both sides. Copy the messages — folder by folder over IMAP, through a provider importer, or with imapsync for large mailboxes — and leave the originals in place as a fallback. Preserve the structure by re-creating folders, translating labels deliberately, and rebuilding filters and signatures by hand. Move contacts and calendar separately via vCard and iCalendar files, because they are not email and will not ride along on their own.

Then protect the transition. Keep both accounts open, connect them in one place so you never lose access, forward the old to the new, and migrate your logins off the old address before you stop watching it. Verify with arithmetic — match message counts folder by folder — and with spot-checks for dates, attachments, threads, and search. Cut over only when the new account is proven, and keep the old one forwarding for weeks to catch the long tail. Do it in that order and a migration that sounds frightening becomes uneventful, which is exactly what you want from one.

The single decision that lowers the risk most is refusing to make it a clean break. Keep both inboxes live in one view, let the copy happen in the background, and retire the old account only when you are certain. That is the whole philosophy behind connecting both accounts in AI Emaily during the move — so you never lose access mid-migration, never miss a message split between two places, and cut over on your own schedule. Migrate carefully, verify honestly, and you will arrive at your new provider with everything intact and nothing left behind.