I recently have been stuck with having to play Steam games on my Mac, and while I have not minded different keys being where I'm used to them on Windows, the real problem I have is that I can't assign 'DUCK' (in Valve games) to Fn, and on my Windows computer that's where Control was.

For other games that I used to use Control for stuff (like LoL) it was very easy to change the keybinding but for Valve games it seems I can't so easily. Any solutions?

  • 3
    As far as I'm aware, Fn isn't sent to the operating system like ctrl, alt, and shift are.
    – Powerlord
    Commented Mar 11, 2015 at 5:29
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    So what you're saying is you've managed to bind Fn to an action in other games (like LoL)? But it's not working in the same way for Valve games? As the commenter above says, I was under the impression Fn wasn't recognized by any OS/software (at least by default), so I'd be interested in hearing how you bound it in games like LoL. Commented Mar 11, 2015 at 7:27
  • As other's have said above, pretty sure Fn only gets to the keyboard's control chip, NOT the PC. It's purpose is to differentiate a different keypress for the OS, so you can push another key and have it interpreted a different way.
    – Robotnik
    Commented Mar 11, 2015 at 8:01

1 Answer 1


Make a macro on an external Driver ( if you are using razor or steelseries etc this is easy) on the button to "be" another button that you wont typically use while gaming. Put this in some predefined "gaming" setting that you can easily switch this setting in when you want to play games where you need this keybind.

So as an example, make a macro that FN will output the letter T when pressed. Then in game you bind T to the action you want. Then when pressing fn a macro will fire that will output T.

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