How Do I Stop Win 11 Updating Outlook

I help and advise a family member to use her win 11 computer. I was on her computer when suddenly the screen was filled with a "message" that windows found a newer version of Outlook and was updating it. I frantically quickly closed that window and apparently the upgrade did not go through. But that was because I was sitting at the computer and saw it. Had I not been there she would have lost the Outlook she uses.

I do not want any version of Outlook on her computer except the version I had installed, which is what she knows and is happy with. How do I prevent arrogant Microsoft from trying to force an upgrade again when I'm not on her computer to stop it? How do I prevent any change to Outlook?.

The version of win 11 is 25H2. Build 26200.9445.

NewWin11User said:

How do I prevent arrogant Microsoft from trying to force an upgrade

Click to expand...

Their product, their rules.

BTW, which of the many variations of o/Outlook is it?

Search result -

1. Hide the "Try the New Outlook" Toggle

You can prevent the toggle from appearing in classic Outlook using the Windows Registry:
• Press Windows + R, type regedit, and hit Enter.
• Navigate to:
HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\Preferences
• Look for or create a DWORD (32-bit) Value named HideNewOutlookToggle.
• Set its value data to 1 to hide the toggle completely.

2. Stop Automatic Migration to New Outlook

To block Windows/Office from auto-migrating your classic Outlook accounts to the new version:
• Open Registry Editor (regedit).
• Navigate to your Outlook registry key and set DoNewOutlookAutoMigration to 0 (if present in your enterprise/local policy tree).
• Alternatively, IT admins use group policies or management tools to disable OneWinNativeOutlookEnabled for Exchange mailboxes.

3. Reverting to Classic Outlook (If It Already Switched)

If Windows or an update already switched you to the new Outlook app:
• Open the new Outlook app.
• Look for the toggle at the top right and click "Switch back to classic Outlook".
• If the toggle is missing, open classic Outlook directly from the Windows Start Menu (search for "Outlook (classic)") rather than the default mail shortcut.