ok its an imac sooo the groundsystem should be mac and windows is only simulated ^^ so he needs to update the macdrivers … but in the end i dont know if stonhearth will be work so …
the only option that i see is the make it working on the macside -
http://discourse.stonehearth.net/t/the-mac-version/12521
and
http://discourse.stonehearth.net/t/tut-mac-linux-users-how-to-get-stonehearth-from-steam-on-your-platform/13381