When I import a new model (never been imported to the Unity project), I'm unable to edit any of the materials in that model. When I select the material in the Project panel, it's dimmed in the Inspector. This just started happening with Unity 2017.3 (MacOS 10.12.6). I can edit the materials of models already in the project, it's just the new ones that I can't. Also, now when I import a model, it creates all new materials in my project, and it puts those materials in the model folder (in the Project panel) along with the meshes. These new models use the same materials as those already in the project, so the new, un-editable materials are all duplicates. Previously, when I added a model that used existing materials, it would not duplicate the materials, and it would not put new materials in the model's folder. I've tried importing a few different new models in native C4D, native Cheetah3D, and FBX, in two different projects, and the result is the same. I've tried all the various import settings, it doesn't make a difference. Short of reassigning all the materials after importing, I don't know what else to try.