Windows 10 fingerprint login changes default login method back to password
Check this article on how to set your default sign-in option in Windows 10 using a registry tweak.
Press the Windows + R keys together, and then type regedit and hit Enter to access Registry Editor.
Navigate to the registry key: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Authentication\LogonUI\UserTile
Find your current account's SID on the right pane, and double-click on it to modify.
Type {D6886603-9D2F-4EB2-B667-1971041FA96B} in the Value data field and click OK.
Reboot your computer and it will display PIN as your default sign-in option on the logon screen.
GUID for each sign-in option:
- PIN: {D6886603-9D2F-4EB2-B667-1971041FA96B}
- Picture Logon: {2135F72A-90B5-4ED3-A7F1-8BB705AC276A}
- Password: {60B78E88-EAD8-445C-9CFD-0B87F74EA6CD}
- Fingerprint Logon: {BEC09223-B018-416D-A0AC-523971B639F5}