diff --git a/speckle_import.py b/speckle_import.py
index d8c807b..372e5a1 100644
--- a/speckle_import.py
+++ b/speckle_import.py
@@ -45,10 +45,12 @@ def set_filename(fileName):
 for mat in bpy.data.materials:
     COLOR = (1.0, 1.0, 1.0, 1.0)
     mat.diffuse_color = COLOR
+    
+    if not mat.node_tree:
+        continue
     inputs = mat.node_tree.nodes["Principled BSDF"].inputs
     inputs["Base Color"].default_value = COLOR
 
-
 # Convert all rooms as lights
 traversal_func = get_default_traversal_func(can_convert_to_native)
 rooms = [x.current for x in traversal_func.traverse(root_object) if x.current.speckle_type == "Objects.BuiltElements.Room"]