Hi Denny Ibbotson,
Welcome to Microsoft Q&A.
Based on your description, here are the two most common causes and how to address them:
1) The “Try the new Outlook” toggle can keep pushing you back to New Outlook.
To stay in Classic Outlook:
- Make sure you're opening Outlook (classic) from the Start menu (not "Outlook (new)").
- If you get flipped to the new version, use the "Try the new Outlook" toggle to switch back.
For reference: Toggle out of the new Outlook for Windows
2) Removing the @outlook.com alias
Important: Removing an @outlook.com alias from your Microsoft account is permanent and cannot be undone. If that address is tied to your sign-in, purchases, or subscriptions, it's safer to first remove it from the Outlook app (which only disconnects it locally) rather than deleting it from your Microsoft account entirely.
For reference: Add or remove an email alias in Outlook.com
If Classic Outlook keeps prompting for sign-in, try these steps:
- In Classic Outlook: File > Account Settings > Account Settings: If @outlook.com is listed as a separate account you don't use, select it > Remove (this only removes it from the app).
- If Classic keeps prompting for sign-in:
- Close Outlook.
- Open Windows Credential Manager > remove entries related to Outlook/Microsoft/Office. Note: Modifying Credential Manager affects stored credentials system-wide. Only remove entries specifically related to Outlook/Microsoft/Office to avoid affecting other apps.
- Reopen Outlook and sign in once.
If you can share the exact error message or sign-in prompt you're seeing, and confirm whether your email is an @outlook.com address or from another provider (like Gmail, Yahoo, etc.), I can provide more targeted steps.
Please let me know if this proves useful to you, or if you would like further assistance.
I'm looking forward to your reply.
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