How to Switch Between New Outlook and Classic Outlook for Windows

You want to move between the new Outlook for Windows and classic Outlook — either to try the new app, or to get back to the familiar one — but you can’t find where to flip it.

Why this trips people up: there are now two completely separate apps. “New Outlook for Windows” is the streamlined app that started as Mail/Calendar’s replacement; “classic Outlook” is the full desktop Outlook you’ve used for years. There’s no setting buried in Options — the switch is a single toggle in the top-right corner of whichever app you’re in. Note this is different from Outlook.com (the website) and from the Outlook mobile app.

Fix 1: Switch from new Outlook back to classic

1. In the new Outlook for Windows, find the toggle at the top right of the window (labeled New Outlook).
2. Click it. You’ll see two choices:
   • Switch back to classic Outlook — sends you to classic Outlook for good. After this, launching Outlook opens classic Outlook instead of redirecting to new Outlook. Microsoft asks for quick feedback first.
   • Use classic Outlook this time — opens classic Outlook right now without permanently switching. Your next launch will still open new Outlook.
3. Pick Switch back to classic Outlook if you want classic to be your default again.

Fix 2: Switch from classic Outlook to new Outlook

1. In classic Outlook, look for the Try the new Outlook toggle at the top right.
2. Turn it on. The new app downloads (if needed) and opens, and your accounts and settings migrate automatically.
3. While the toggle is on, trying to launch classic Outlook or Windows Mail automatically redirects you to new Outlook for Windows.

Fix 3: No toggle showing? Force it from the registry

If the toggle is missing — common when an admin policy or an unsupported account type hides it — set the switch manually:

1. Close Outlook.
2. Open Registry Editor (press the Windows key, type regedit, press Enter).
3. Go to HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Preferences.
4. Find the UseNewOutlook value and set its data to 0 to force classic Outlook (set it to 1 to force new Outlook).
5. Launch Outlook from the Start menu.

FAQ

Will I lose mail or settings when I switch? No. Your accounts and most settings migrate automatically, and your mail lives on the server — switching apps doesn’t delete anything.

Can I run both at the same time? Yes, classic and new Outlook can run side-by-side once both are installed; the toggle only controls which one launches by default.

The toggle is greyed out or absent and the registry didn’t help. Your account type may not be supported in new Outlook yet, or your organization has locked the choice — that’s an admin/tenant policy, not something you can override locally.

Sources: Microsoft Support — Toggle out of the new Outlook for Windows