Cannot edit materials

I just imported an fbx model from Max into Unity. It's just a simple model with two surfaces, each with a standard material and a texture. For some reason I can't edit the materials or change the textures. Anyone know why?

 

If you use Unity 2017.3 or newer, one reason why you can't edit the material could be, because the imported model uses the "Use Embedded Materials" option:
https://docs.unity3d.com/Manual/FBXImporter-Materials.html

 

Yes, looks like that was the problem. Thanks.