I am unable to launch the game under OS X 10.10.3 Yosemite.
Macbook Pro Retina Display i7 16GB RAM Late 3013.
If there is a log file you need, just point me to it's location, and I'll send you it.
An attempt to open
Xonotic.app from the terminal using the command
open Xonotic.app after
cd'ing to the /Applications/Xonotic directory, where I extracted the game to returns this error:
LSOpenURLsWithRole() failed with error -10810 for the file /Applications/Xonotic/Xonotic.app.