remove backup email

Yes. A backup email used as a security info method can be removed from the Security info page without accessing that email account.

If the phone number on the Outlook.com account is still available, use that as the verification method and then remove the old email:

1. Sign in to the Microsoft account security settings.
2. Open the Security info page.
3. If needed, add or confirm the phone as a sign-in or verification method.
4. On the Security info page, select Delete next to the Email method.
5. Select Yes to confirm.

Important:

• If the email is deleted by mistake, it cannot be undone; it must be added again.
• Do not change all security info at the same time, because the account may be restricted for 30 days.
• If sign-in asks for a code from methods that are no longer accessible, select I don't have any of these and follow the prompts.

References:

• Set up an email address as your verification method | Microsoft Support
• Common problems with two-step verification for a work or school account