just found a solution that worked for me and want to spread the word.
this was with a brand new out of the box USB fingerprint reader form FocalTech. i had tried all of the solutions in many different posts to no end. in a last ditch attempt i was looking though the Event Viewer for any clues and saw some verbose level messages under:
Event Viewer (Local) / Application and Services / Microsoft / Windows / Biometrics / Operational
with the message:
The Windows Biometric Service cannot complete a request because biometric operations are disabled by current system policy.
if you see this message, then you can try the following which worked for me:
as Administrator open Policy Editor
select Local Computer Policy / Computer Configuration / Administrative Templates / Windows Components / Biometrics
double click "Allow the use of biometrics", which should say "Not Configured"
click the Enabled radio button, then Apply
click the Not Configured radio button, then Apply
you should not need to reboot, but you can if you like
go to the Accounts > Sign-in options and the fingerprint recognition option should now be available
hope this helps someone!