I have Arnold selected as my renderer. In the material manager, I select CREATE>ARNOLD>SURFACE>STANDARD SURFACE. The material window opens with all the settings, but the material icon in the manager comes up black. I can adjust the shader, rename it, drag it to an object, and it correctly covers that object in the IPR window. Yet, the material manager icon remains black. I suspect I have some setup parameter wrong. How can I fix this?
While the IPR is running the material previews are not rendered. It's a limitation in Arnold. A small orange frame indicates this in the preview. When you stop the IPR the previews should update.
If your previews are black when the IPR is off and no other renders are running then it could be a bug. Please contact the support in this case.