I have found that I will get that same error if I try to render any material which uses a "curve" node, such as RGB Curve or Vector Curve Nodes. I don't believe these curve nodes are supported by ProRender yet. So if you are using that node anywhere in your problem scene, I would try removing it to see if the error goes away.![blender_gQlP5yrvDs.png blender_gQlP5yrvDs.png](/t5/image/serverpage/image-id/23328i8B708D4ACE782D09/image-size/large?v=v2&px=999)