A2F DOESN'T WORK

Because the PIN was lost after the BIOS update, the account must be accessed using another sign-in method and the verification-code issue resolved first.

Follow these steps in order:

1. Try another verification/sign-in method

• On the Microsoft sign-in or verification screen, choose a different method if available:
  • Email code to a backup email address
  • Microsoft Authenticator app
  • Security key or other method already configured
• If another method works, sign in and then:
  • Go to Settings → Accounts → Sign-in options in Windows and remove the old PIN.
  • Add a new PIN.

2. Fix the missing SMS verification code If SMS is the only method and the code is not arriving, check the following from the guidance:

• Do not repeatedly request new codes; excessive or repetitive requests can cause Microsoft to temporarily block sending verification codes.
• Make sure the phone can receive SMS from unknown numbers. If it blocks them, change the phone settings, then on the verification page choose I don't have a code to have another code sent.
• Confirm that the phone number is a mobile number, not VOIP. VOIP numbers cannot be used to receive Microsoft verification codes.
• Ensure the number and country code are correct when shown on the verification screen (only the last two digits are visible for security).
• If in a region where Microsoft’s SMS services are limited or temporarily unavailable, or if there is heavy compromised traffic from the location, delivery may be delayed or blocked. In that case, wait and try again later.

3. If all security info is inaccessible If no verification method works (no SMS, no email, no Authenticator), use the account recovery process:

• For a personal Microsoft account, follow the steps in Help with the Microsoft account recovery form and then submit the recovery form via Recover account.
• Be aware that if all security info is replaced, access may be restricted for up to 30 days before normal sign-in is allowed.

4. If the Windows device is still inaccessible

• Use any working method (password, recovery form result, or another device where already signed in) to regain access to the Microsoft account first.
• Once account access is restored, on the Windows sign-in screen choose I forgot my PIN and complete the verification using a working method (email, Authenticator, etc.) to set a new PIN.

If codes still never arrive after following the above, use the Sign-in helper and, if needed, Contact Microsoft Support for additional troubleshooting of the verification-code delivery (support cannot send codes or change security info but can help diagnose).

References:

• Troubleshoot Microsoft verification code issues
• Common problems with two-step verification for a work or school account