For now Carrara does not run on the Mac based on Intel processors so not it would not work. We are planning to release a version of Carrara for the platform later on. You can mix Mac and PC in a network rendering. It works in most cases but sometimes there are problems. For instance, physics do not give the same result on Mac and Windows so you end up with disconnected tiles... I would recommend not mixing the platforms if possible. You will get the best results by using the same platform.