How to mute sound alert when a key is not recognized? I'm pressing F16 and it's not bind to anything and it's making a sound, like bip alerting me that the command is not found. How can I mute this sound?
You can completely disable alert sounds. If it's right for you, do it this way :

Go to System Preferences.app &gt; Sound &gt; Sound Effects
Mute the Alert Volume using the slider