Material editor materials corruption

I am using brazil with rhino and rhinogold. I am making a ring that uses a custom material. I am using material editor to edit the preset materials from rhinogold. In material editor all materials I have ever applied to the scene show a preview thumbnail. I have rendered several views of the scene and closed my file. the next time I open the file and render some of the materials display darker in the material editor preview and then they render that way as well. I have tried everything I can think of including deleting the material from the editor box and reloading it but the material still shows dark and non reflective.
I cannot even use any of the components of the scene in another scene, as in export an object then import it into a new scene because the corrupt material follows the object. I also cannot re-apply a material from rhinogold materials once I have deleted it from the editor box.
does anyone have any ideas about these materials corrupting? I have brazil installed on my laptop and my desktop. I have opened the file from the cloud on the other computer and the corruption of the material stays with the file even on a different machine.
Thanks Greg

I’m not sure what the issue might be but have you contacted RhinoGold support yet? I’m wondering if the preset materials you’re editing have lost a texture map or if a gamma value changes when they are edited. I do not have RhinoGold here to test this but I’d suggest trying to make the material you want from scratch too. See if you can find the texture maps, if any, that the preset material uses on your system first to assign them directly.