Hi Mike Lee
I'm sorry to hear that you're running into this. The A1B2C3 prompt appears when Windows has detected multiple incorrect PIN attempts and is requiring an additional verification step before allowing another sign-in attempt. If you no longer remember the PIN and do not see a reset option, try the following:
- On the sign-in screen, select Sign-in options and check whether you can sign in using your Microsoft account password instead of the PIN.
- If you can sign in with your password, go to Settings > Accounts > Sign-in options > PIN (Windows Hello) > I forgot my PIN and follow the prompts to create a new PIN.
- If no other sign-in method is available and you cannot access Windows, you may need to use Surface Recovery or Reset this PC from the Windows Recovery Environment. Be aware that a full reset can remove apps and personal files.
If BitLocker recovery is triggered during recovery, you may also need your BitLocker recovery key before proceeding.
If you can tell us whether you're using a Microsoft account or a local account, and whether any password sign-in option is available, that could be of help.
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