Is your password expired ? Can you try changing your password and see whether you are able to unlock with the new password ?
If you still see the problem can you post "/var/log/auth.log" after trying to unlock the screen.
Is your password expired ? Can you try changing your password and see whether you are able to unlock with the new password ?
If you still see the problem can you post "/var/log/auth.log" after trying to unlock the screen.