To restore Classic Outlook after Microsoft 365 replaces it with the new Outlook for Windows, download it from the Microsoft Store using this direct link: apps.microsoft.com/detail/xp9mhd8pgh9n47. The app does not appear in Store search results, but installing it from that link pulls the classic version back onto your PC — your existing mail profile, PST files, and accounts load automatically when you open it.
Applies to: Windows 10 (22H2) and Windows 11 (23H2, 24H2, 25H2) with Microsoft 365 / Office 2021 / Office 2024 | Last updated: April 19, 2026
Key Takeaways
- Microsoft is silently replacing Classic Outlook with the free, ad-supported New Outlook for Windows during clean Microsoft 365 installations and some updates to existing installs.
- Classic Outlook is still available on the Microsoft Store, but you cannot find it through Store search — you need the direct link.
- Your existing mail profile is not deleted when Outlook disappears. Reinstalling Classic Outlook restores all accounts, PST files, and signatures exactly as they were.
- POP3 accounts and PST files are only fully supported in Classic Outlook — the new Outlook still does not read PST files as of April 2026.
- Three registry keys (
NewOutlookMigrationUserSetting,UseNewOutlook,DoNewOutlookAutoMigration) prevent Microsoft from swapping Classic Outlook for the new app again.
Quick Steps
- Open the Microsoft Store link for Classic Outlook: apps.microsoft.com/detail/xp9mhd8pgh9n47.
- Click Get in Store app, then Install in the Microsoft Store window that opens.
- Launch Classic Outlook — your mail profile, PST files, and accounts reappear automatically.
- (Optional) Uninstall the New Outlook for Windows app from Settings > Apps > Installed apps.
- (Optional) Run three
reg addcommands in an elevated terminal to block Microsoft from replacing Classic Outlook again.
In This Guide
This guide walks through two things: restoring Classic Outlook, and preventing it from disappearing again.
- Why Classic Outlook disappears from Microsoft 365 — the two scenarios I have seen in the repair shop.
- POP3 vs. IMAP, and why this matters — the reason the disappearance is a real problem, not just an annoyance.
- Restore Classic Outlook from the Microsoft Store — the working fix.
- Prevent the swap from happening again (registry) — three registry keys to lock it in.
Why Classic Outlook Disappears from Microsoft 365
Microsoft is migrating users from the paid desktop version of Outlook to the free New Outlook for Windows app. I first hit this at the repair shop with a client who had a clean Microsoft 365 installation: every Office app — Word, Excel, PowerPoint — installed correctly, but Classic Outlook was nowhere to be found. A Windows search returned nothing, and the usual C:\Program Files\Microsoft Office\root\Office16 folder did not contain OUTLOOK.EXE.
A few days later, a different client called in panicking: their Outlook had “completely vanished” overnight on a PC that had been working fine for years. That one was an existing Microsoft 365 installation — the New Outlook for Windows had replaced Classic Outlook during a silent update. They had four POP3 accounts with years of client data in PST files, and none of it was accessible through the new app.
The swap happens in two scenarios:
- Fresh installs of Microsoft 365 — Classic Outlook is simply not included.
- Existing installations — a background update removes Classic Outlook and installs the New Outlook app in its place.
In both cases the mail profile is left intact on disk. That is why the fix below works so smoothly — you are not re-adding accounts, just putting the Classic Outlook binary back.
POP3 vs. IMAP, and Why This Matters
Classic Outlook and the New Outlook for Windows handle email storage differently, and that difference is the whole reason this swap is painful for business users.
POP3 (supported in Classic Outlook with PST files):
- Emails are downloaded to a PST file (Personal Storage Table) on your local disk.
- Every email is a true offline copy — you can read them with no internet connection, even years later.
- You control when (or if) messages are removed from the server. If someone gains access to the mail server and deletes everything, your local PST copy is untouched.
IMAP (used by both Classic and New Outlook, with OST files):
- Emails are synchronised to an OST file (Offline Storage Table) that mirrors the server.
- Only the most recent messages are truly offline. Older emails often need to be re-downloaded from the server when you open them.
- Delete on the server = delete in Outlook, and vice versa. Good for multi-device workflows; bad if the server is compromised or the account is closed.
As of April 2026 the New Outlook for Windows still does not support opening PST files. For anyone with years of client correspondence stored in a PST — freelancers, small-business owners, accountants — losing Classic Outlook means losing read access to all of that history. That is why “just use the new app” is not a real answer.
Free download: I made a one-page infographic summarising all of this (PST vs. OST, POP3 vs. IMAP, what each Outlook version supports). Grab it from Gumroad — enter 0 as the amount for a free download.
Restore Classic Outlook from the Microsoft Store
Here is the fix that worked in both cases I dealt with in the shop. It is the same fix the Reddit sysadmin community landed on when this started rolling out.
- Open the direct Microsoft Store link for Classic Outlook: apps.microsoft.com/detail/xp9mhd8pgh9n47. Do not try to search for it inside the Store — it will not come up, and all you will get are results for the New Outlook for Windows.
- Click Get in Store app. When the Microsoft Store window opens, click Install. The download is small and finishes in under a minute.
- Launch Outlook (classic) from the Start menu. Your mail profile loads automatically — all accounts, PST files, folders, signatures, and rules return exactly as they were before.
- Verify that older emails in your PST files are readable. Open a message from years ago; if it displays instantly with no “downloading from server” prompt, you are fully back on Classic.
- (Optional) Go to Settings > Apps > Installed apps, find Outlook (the New Outlook entry, often labelled “Outlook for Windows”), and uninstall it to avoid confusion between the two icons.
If the Microsoft Store itself is missing from the PC (which can happen after aggressive Windows debloats), reinstall it first using my guide on how to reinstall the missing Microsoft Store on Windows 10 & 11, then come back and follow the steps above.
Prevent the Swap From Happening Again (Registry)
Once Classic Outlook is back, three registry keys block Microsoft from migrating users to the New Outlook for Windows again. These were surfaced by the r/sysadmin community and they have held up in my own testing over several Microsoft 365 update cycles.
Before you continue: Registry changes can break things if mistyped. Create a restore point (Create a restore point in the Start menu search, then click Create) before running the commands below.
Open Windows Terminal, PowerShell, or Command Prompt as Administrator (right-click the Start button and choose the “(Admin)” variant), then run these three commands one by one:
reg add "HKCU\SOFTWARE\Policies\Microsoft\Office\16.0\Outlook\Preferences" /v NewOutlookMigrationUserSetting /t REG_DWORD /d 0 /freg add "HKCU\SOFTWARE\Microsoft\Office\16.0\Outlook\Preferences" /v UseNewOutlook /t REG_DWORD /d 0 /freg add "HKCU\SOFTWARE\Microsoft\Office\16.0\Outlook\Options\General" /v DoNewOutlookAutoMigration /t REG_DWORD /d 0 /fWhat each one does:
- NewOutlookMigrationUserSetting = 0 — blocks the user-level migration prompt that pushes you from Classic to New Outlook.
- UseNewOutlook = 0 — forces Classic Outlook as the default when both are installed.
- DoNewOutlookAutoMigration = 0 — disables the automatic background migration that Microsoft runs during Office updates.
If you are on Windows 11 and want a similar registry tweak to stop the New Outlook from being installed at all, see my post on how to prevent New Outlook installation on Windows 11.
Why This Matters (A Quick Rant)
Classic Outlook is part of the paid Microsoft 365 suite. It cannot be purchased standalone. The Office licenses that include it cost noticeably more than the ones that do not. Some of my clients buy Office specifically because they need Classic Outlook — Word and Excel have excellent free alternatives; Outlook does not.
Microsoft replacing a paid app with a free, ad-supported app that lacks key features — silently, without consent — is not an acceptable migration path. If the goal was to simplify, the honest route would have been to make Classic Outlook free and hand out the New Outlook as a separate download. Until that changes, the workaround in this guide is the only way to get the version you paid for back.
Related Guides
- Prevent New Outlook Installation on Windows 11 (Registry)
- Keep Attachments When Replying in Microsoft Outlook
- Install Missing Microsoft Store on Windows 10 & 11
- Winhance — my free Windows optimisation utility
Frequently Asked Questions
Why is Microsoft replacing Classic Outlook with the new Outlook app?
Microsoft is consolidating Outlook for Windows, Outlook on the web, and the Mail app in Windows 11 into one unified codebase — the New Outlook. The trade-off is that the new app is still missing features Classic users rely on, most notably PST file support and full POP3 handling.
Will my PST files and accounts be wiped when Outlook disappears?
No. The Outlook mail profile and PST files sit in %LOCALAPPDATA%\Microsoft\Outlook and are untouched by the migration. Reinstalling Classic Outlook from the Microsoft Store picks everything back up automatically — nothing needs to be re-added.
Do I need a Microsoft 365 subscription to use Classic Outlook from the Store?
Yes. Even though you download it from the Microsoft Store, the app will not run without a valid Microsoft 365, Office 2021, or Office 2024 license. It is the same paid application — the Store is just a new distribution channel for it.
Does the new Outlook for Windows support PST files yet?
As of April 2026, no. Microsoft has said PST support is on the roadmap, but there is no public release date. If your workflow depends on PST files, stay on Classic Outlook.
Can I run Classic Outlook and the new Outlook side by side?
Yes, both can be installed at the same time — they register as separate apps. I recommend uninstalling the New Outlook once Classic is working, because the two Start menu icons look similar and users frequently open the wrong one. If you keep both, pin only the Classic shortcut to your taskbar.
