Have you already succeed to connect your Mac with the Sigma with USB ?
In my case, I used my Windows Session on my Mac because I can't connect it. I tried a tutoriel on internet to install special Arduino like drivers for my Mac, but the problem persist. I never had this trouble with my old Ultimaker.
I think that Ultimaker used a genuine Arduino board instead of BCN3D. And this board is not recognized by an Apple computer.
Have you already succeed to connect your Mac with the Sigma with USB ?
In my case, I used my Windows Session on my Mac because I can't connect it. I tried a tutoriel on internet to install special Arduino like drivers for my Mac, but the problem persist. I never had this trouble with my old Ultimaker.
I think that Ultimaker used a genuine Arduino board instead of BCN3D. And this board is not recognized by an Apple computer.