How to Migrate Mail, Folders and Rules to the New Outlook App

Moving from classic Outlook to the new Outlook app sounds simple, until you open the new app and wonder where your folders, rules, and years of organised mail have gone. The good news is that most of your mail lives on the server, not inside the old program, so a careful migration brings almost everything across. The key is knowing what transfers automatically, what needs exporting, and what you must rebuild by hand.

Quick Answer

For Microsoft 365 and Outlook.com accounts, mail, folders, and calendar data sync automatically when you add the same account to the new Outlook. Server-side rules usually carry over, but rules created only in classic Outlook, along with local PST files, signatures, and some settings, must be exported or recreated. Back up your PST files and export your rules before you switch, then add your accounts to the new app and check each item.

Understand What Lives Where Before You Move

A smooth migration starts with one simple question: where is your data actually stored? The answer decides how much work you have to do.

Mail for Microsoft 365, Exchange, and Outlook.com accounts is stored on Microsoft’s servers. Classic Outlook only keeps a local copy. When you sign in to the new Outlook with the same account, the server copy flows down again, complete with your folder structure.

POP accounts and archive files are different. POP downloads mail to your computer, and PST archive files exist only on your hard drive unless you back them up. Those items need manual handling, and losing track of them is the single biggest migration risk.

The Three Types of Outlook Data

• Server mail and folders: Inbox, Sent Items, custom folders, and subfolders for Exchange, Microsoft 365, and Outlook.com accounts.
• Local files: PST archives, old POP downloads, and saved attachments stored only on your PC.
• Personal settings: Rules, signatures, categories, Quick Steps, and view preferences, some of which live in the profile rather than the mailbox.

Step One: Back Up Everything in Classic Outlook

Never start a migration without a backup. It takes a few minutes and turns every later mistake into a minor inconvenience instead of a disaster.

1. Open classic Outlook and go to File, then Open and Export, then Import and Export.
2. Choose Export to a file, then Outlook Data File (.pst).
3. Select your top-level mailbox folder and tick Include subfolders.
4. Save the file somewhere safe, ideally an external drive or cloud folder, not just your desktop.
5. Repeat the export for any separate archive PST files you rely on.

While you are there, note the exact locations of any PST files classic Outlook currently opens. Go to File, Account Settings, then the Data Files tab to see every file in use. Our detailed walkthrough of how to back up and restore Outlook PST files safely explains safe storage options if you want more depth.

Step Two: Export Your Rules From Classic Outlook

Rules are the item users miss most after switching. Some rules run on the server and follow your mailbox anywhere. Others run only when classic Outlook is open, and those client-only rules do not travel on their own.

1. In classic Outlook, go to File, then Manage Rules and Alerts.
2. Select Options in the Rules and Alerts window.
3. Choose Export Rules and save the .rwz file with your backup.
4. Take a screenshot or write down complex rules, because you may rebuild some of them manually.
5. Note which rules say “on this computer only” — those are the ones the new app will not inherit automatically.

The new Outlook supports many common rules, such as moving mail from a sender to a folder, but a few classic actions are missing or work differently. Microsoft’s own Microsoft support guide to managing email with rules in Outlook lists the actions available in the new experience.

Step Three: Add Your Accounts to the New Outlook

With backups safe, you can now set up the new app. Install or open the new Outlook for Windows and sign in with your main Microsoft account first.

1. Open the new Outlook and select Add account when prompted.
2. Enter your full email address and complete the sign-in, including any multi-factor prompt.
3. Wait for the initial sync to finish — large mailboxes can take an hour or more on a slow connection.
4. Check that your folders and subfolders appear in the left pane in the right order.
5. Add any additional accounts, such as Gmail or a second work account, one at a time.

Do not judge the migration in the first five minutes. Headers arrive first and older mail fills in gradually. Compare folder counts a day later if your mailbox is very large, and keep classic Outlook installed until you are fully confident.

Step Four: Import Local PST Files

If you kept archives in PST files, import them so the mail becomes part of your server mailbox, where it is backed up and searchable everywhere. Recent versions of the new Outlook include a PST import option in Settings under General and Import; availability can vary by version and account type.

1. In the new Outlook, open Settings and look for the Import section.
2. Choose the option to import a PST file and select your backup file.
3. Pick the destination folder, ideally a clearly named archive folder in your mailbox.
4. Start the import and let it complete without closing the app.
5. Spot-check old messages, dates, and attachments once the import finishes.

Very large PST files import slowly and may need splitting in classic Outlook first. If the new app offers no import option for your account, the safe fallback is to import the PST into classic Outlook connected to your mailbox, let it sync to the server, and then open the new app.

Step Five: Recreate Signatures, Categories, and Missing Rules

Now rebuild the personal touches. Signatures do not reliably transfer between the two apps, so paste your signature text from a sent email and save it fresh in the new Outlook under Settings, Accounts, and Signatures.

Categories usually sync for Microsoft accounts, but colours may reset. Check your category list, rename anything unclear, and reassign colours where needed. Then open Settings, Mail, and Rules in the new Outlook and compare the list against your notes. Recreate any client-only rules using the new conditions, and test each one by sending yourself a message that should trigger it.

Common Mistakes to Avoid

• Deleting classic Outlook too early: Keep it installed until mail, rules, and archives are all verified in the new app.
• Assuming POP mail is on a server: POP mail may exist only in a local file. Back it up before anything else.
• Forgetting shared mailboxes and calendars: Re-add shared folders and check calendar permissions after the move.
• Skipping the rule test: A recreated rule with one wrong condition silently files mail in the wrong place for weeks.
• Importing the same PST twice: Duplicate imports create duplicate mail. Import once, verify, and keep the file as a backup.

Conclusion

Migrating from classic Outlook to the new Outlook is mostly a sync job for Microsoft 365 and Outlook.com accounts, and a careful manual job for PST archives and client-only rules. Back up first, export your rules, add your accounts, import local files, and rebuild signatures and missing rules. Done in that order, you keep your mail, your folders, and your hard-won organisation intact.

Frequently Asked Questions

Will all my folders appear automatically in the new Outlook?

Yes, for Microsoft 365, Exchange, and Outlook.com accounts, because those folders live on the server. Sign in with the same account and allow time for syncing. Folders stored only inside a local PST file must be imported manually before they appear.

Do Outlook rules transfer to the new Outlook?

Server-side rules generally transfer with your mailbox. Rules marked as running on this computer only were stored in classic Outlook and usually need recreating. Exporting your rules to an .rwz file and noting each rule down makes rebuilding them much faster.

Can I still use classic Outlook after migrating?

Yes. Both apps can sit on the same PC, and many users keep classic Outlook during a transition period. Just avoid editing the same rules in both apps at once, and remember Microsoft is gradually retiring the classic interface in favour of the new app.

What happens to my archived PST mail if I do nothing?

It stays in the PST file on your computer and will not appear in the new Outlook. The file is not deleted by switching apps, but it is at risk if the PC fails. Import it into your mailbox or keep at least two backup copies.

Why is some very old mail missing after I switch?

The new Outlook may still be syncing, or classic Outlook may have kept older mail only in a local archive. Wait for syncing to finish, check your folder counts, and import your PST archives. In most cases the mail exists — it just has not arrived in the new view yet.