Hello,
The duplicate user glitch almost always happens when netplwiz was used for auto-login, it got confused between a local account and your Microsoft account. I need a few specific details about what your lock screen is actually showing so we can figure out which credential it is demanding.
- How did you turn off auto-login initially? Was it through
netplwiz, the registry, or somewhere in Settings? - Look at the bottom-left corner of your sign-in screen. Are there still multiple accounts listed there, and if you click between them, does the name above the password box change?
- Right above the password field, does it show your full Microsoft account email address, or does it only display a local username? Also, do you see a Sign-in options link right below the password field?
- When you type the password and click the eye icon to reveal it, does it match your actual password character for character, just in case the keyboard layout switched?