This is really frustrating me. I have a Microsoft Sculpt USB keyboard and have just got a new Macbook Pro with touch bar, and it is just not pairing with the keyboard.
The keyboard connects via a Nano tranceiver, which is plugged into my USB-C port via an adaptor. I can see that this is successfully connected in my system information:
The first time I connected the keyboard, I got a keyboard setup assistant dialogue as described in this question prompting me to press some keys on the keyboard to set it up. When I press the keys as requested, nothing happens.
Now, nothing pops up, and the keyboard is just completely unresponsive. However, I can see the keyboard is there as one of my input sources when I click 'Modifier Keys…' in my keyboard system preferences: 
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Really pretty stuck on what to do here. I can't find any drivers or other settings that I might change to fix this.
Best Answer
https://www.themtparty.com/karabiner-settings-microsoft-sculpt-keyboard/
the Karabiner download allowed my Sculpt keyboard to work on my El Capitan system. I'm excited as the keyboard suddenly stopped working a few weeks ago for no reason. Happy for this download, will donate coffee $ as suggested