Originally Posted by ymr_raghu
How to unlock the user Password.
You don't have to reset the password as mentioned or reboot. I'd be damned if I get locked out of a production system and it requires a reboot in order to get back in, that would be the dumbest design ever. Same with resetting of the password. You just need to reset the user with the faillog command.
faillog -r <username>
That will reset the fail attempts and the user can resume logging in.
man faillog for more details.