New outlook keeps opening instead of classic

If Outlook keeps opening the new app, common causes include Windows default app settings, the account tile you are signing into, or whether classic Outlook is installed at all. Fixing the wrong one wastes time and can leave mail, add-ins, or shared calendars unavailable. This guide shows how to tell each case apart and fix the exact cause.

What the wrong Outlook opening means

The first step is to identify where the wrong app appears: from the Start menu, from a pinned taskbar shortcut, or only when you open an email link. That tells you whether you are dealing with a launch-default problem, a shortcut mismatch, or a mailto association issue.

Say your Start menu opens Outlook, but the app shows the modern interface with the top-right toggle. That points to New Outlook for Windows, which can send you back into the new experience while the toggle is on. If Start shows Outlook (classic) and it still opens the modern app, the startup preference or a redirect setting is the more likely cause.

Why Outlook keeps opening the new version instead of classic

The most common reason is that the New Outlook toggle is on, so launching classic Outlook for Windows or Windows Mail redirects to New Outlook for Windows. If classic Outlook is installed, the fastest fix is to switch from inside the new app, then reset the startup preference if it keeps returning to the modern app. (per Microsoft support)

1. Open New Outlook.
2. Use the toggle in the top-right corner.
3. Select Switch back to classic Outlook if you want the desktop app to remain the default.
4. If you need classic Outlook only for this launch, select Use classic Outlook this time.
5. If Outlook still opens the new app after that, press Win + R, type outlook.exe /firstrun, and press Enter.

A common first-timer mistake is to click the generic Outlook tile and assume it is the desktop app. On systems with both versions installed, that tile may point to the modern app unless the shortcut is tied to Outlook (classic).

How do you stop a shortcut from opening New Outlook?

Taskbar and Start menu shortcuts often point to the wrong app after a switch or update. Pin the desktop version directly, and remove any shortcut that points to the generic Outlook entry. Microsoft says the classic app appears as Outlook (classic) in the app list. (per Microsoft support)

1. Open the Start menu.
2. Search for Outlook (classic).
3. If it appears, open it directly.
4. Right-click Outlook (classic) and choose Pin to taskbar.
5. Unpin any existing Outlook taskbar shortcut that opens the modern app.
6. Use the new pinned shortcut to confirm it opens the classic desktop version.

If both versions appear in Start, choose the one that explicitly says Outlook (classic). That avoids opening the new app by mistake the next time you start from the taskbar.

How do you make email links open Outlook classic?

If mail links in a browser or another app open New Outlook instead of classic Outlook, Windows is probably set to use the modern app for mailto: links. Change the default mail handler in Windows, then test another link to confirm the association changed. This affects email links more than direct app launches.

1. Open Settings.
2. Go to Apps > Default apps.
3. Search for MAILTO or the email default.
4. Choose Outlook (classic) if it is listed.
5. Open a mail link from a browser or another app to test the change.
6. If the modern app still appears first, continue to the registry step below.

Where is the setting to turn off automatic switching to new Outlook?

The key startup preference is the UseNewOutlook value in HKCU\Software\Microsoft\Office\16.0\Outlook\Preferences. Set it to 0 to keep Outlook from preferring the new app, and create it as a DWORD if it is missing. For some installations, this is the cleanest way to stop the app from reverting. (per Microsoft support)

1. Open Registry Editor.
2. Go to HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Preferences.
3. Find UseNewOutlook.
4. Set the value data to 0.
5. If the value does not exist, create a DWORD (32-bit) Value named UseNewOutlook and set it to 0.
6. Close Registry Editor and reopen Outlook from Start.

What if the Outlook toggle is missing in classic Outlook?

If you do not see the toggle, classic Outlook for Windows may not be installed on the device. The same source notes that you may not see the toggle if the classic app is missing, and the classic app is referenced as Outlook (classic) in the app list. (per Microsoft support)

1. Open the Start menu and search for Outlook (classic).
2. If it appears, open it directly and check whether the top-right toggle is available in the new app.
3. If Outlook (classic) does not appear, repair or reinstall Microsoft 365 so the desktop app is installed.
4. After repair or reinstall, search Start again for Outlook (classic).
5. If the entry appears, pin it as a separate taskbar shortcut.

Suppose a laptop has only the modern app after a fresh Microsoft 365 setup. In that case, the switch-back toggle may never appear because the desktop program is not present. Installing the classic app first matters more than changing preferences later.

Why does Outlook switch back after every restart or Windows update?

If the app keeps returning to New Outlook after a restart, there may be a migration setting reapplying the modern app choice. Two registry values matter here: DoNewOutlookAutoMigration in HKCU\Software\Microsoft\Office\16.0\Outlook\Options\General, and NewOutlookAutoMigrationRetryIntervals, which can re-trigger prompts. Set both to 0 to stop the migration flow and repeated nagging. (per Microsoft support)

1. Open Registry Editor.
2. Go to HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Options\General.
3. Set DoNewOutlookAutoMigration to 0.
4. Find NewOutlookAutoMigrationRetryIntervals and set it to 0.
5. Close Registry Editor.
6. Restart Outlook and confirm the desktop app stays selected.

If the switch still comes back on a restart, check whether the device is managed. A work or school policy can override the local preference.

How do you disable the new Outlook redirect on a work or school PC?

On managed devices, the Admin-Controlled Migration to New Outlook policy can force the redirect even when the user changes settings. In that case, the local toggle or registry change may not hold, and IT or the Microsoft 365 admin needs to adjust the policy. This is the right next step when personal fixes fail on a corporate device.

1. Open Outlook (classic) from Start if it is available.
2. Check whether the top-right toggle still switches back after sign-out or restart.
3. If it does, contact your IT admin and ask them to review the Admin-Controlled Migration to New Outlook policy.
4. On a managed device, do not keep reapplying local fixes if policy resets them at the next sign-in.

Why New Outlook opens instead of classic: decision table

Frequently asked questions

Why does Outlook keep opening the new version instead of classic?

The usual cause is that the New Outlook toggle is still on, so classic Outlook redirects into the modern app. Open New Outlook, switch back from the top-right toggle, and then confirm that Outlook (classic) is the app you launch from Start. If it reverts, reset UseNewOutlook to 0.

How do I stop new Outlook from launching when I open Outlook?

Open Outlook (classic) from the Start menu, then pin that entry as its own taskbar shortcut. If the toggle in New Outlook is on, choose Switch back to classic Outlook. For repeated relaunches, run outlook.exe /firstrun once and check the registry preference.

How do I make email links open Outlook classic instead of new Outlook?

Go to Settings > Apps > Default apps, find the MAILTO handler, and assign it to Outlook (classic) if that option is available. Then open a mail link from a browser or another app to confirm the change. This affects links, not necessarily the Start menu shortcut.