In Mavericks, the app simply crashes if you press the enter button a few times. Upon crashing, your computer is unlocked and completely accessible. As a result, the app is totally useless in its current form; it leaves your system completely unprotected. Note to developers: The app comes with a feature that snaps a photo of someone trying to gain access to your computer (by entering the wrong password or simply pressing enter several times). I think this feature is causing the app to crash in Mavericks.