Build 10149 was the first build we released externally to Insiders after we made some changes to our Passport infrastructure. Some users may find that their PIN and Windows Hello has stopped working once they receive an automated build upgrade to Build 10149 (or higher).

If this happens to you, reset your PIN by going to Settings > Accounts > Sign-in options and clicking on “I forgot my PIN”. Note that the PINs for all users on the device must be reset this way for any PIN or Windows Hello to start working again.