Hi d-larsen, this section from the SR4 readme might help you: Material Room ------------- - Corrected an erroneous condition where multiple, disconnected nodes were added to the background color node. As a result, the background color was not editable any more. This problem is fixed in SR4. However, if you still happen to have files where this condition is present, there are a couple simple steps you should take to correct them: 1. Open the problematic file 2. Go to the material room 3. From object menu select background. You'll recognize that there are duplicated nodes. 4. Select and cut/delete all duplicated nodes except for the "BG Color" node that was originally connected to the Background root node. 5. Save the scene. In case you have set to open new documents with your preferred state, the problem still will reproduce in files created by File->New. Please repeat the process described above after creating a new file and set the preferred state again.