diff --git a/source/blender/blenkernel/intern/depsgraph.c b/source/blender/blenkernel/intern/depsgraph.c
index 79beb900306..692c696803d 100644
--- a/source/blender/blenkernel/intern/depsgraph.c
+++ b/source/blender/blenkernel/intern/depsgraph.c
@@ -366,7 +366,7 @@ static void dag_add_material_nodetree_driver_relations(DagForest *dag, DagNode *
 		if (n->id && GS(n->id->name) == ID_MA) {
 			dag_add_material_driver_relations(dag, node, (Material *)n->id);
 		}
-		else if (n->type == NODE_GROUP) {
+		else if (n->type == NODE_GROUP && n->id) {
 			dag_add_material_nodetree_driver_relations(dag, node, (bNodeTree *)n->id);
 		}
 	}
diff --git a/source/blender/blenkernel/intern/material.c b/source/blender/blenkernel/intern/material.c
index 7e8e5455df5..ac072832707 100644
--- a/source/blender/blenkernel/intern/material.c
+++ b/source/blender/blenkernel/intern/material.c
@@ -1071,7 +1071,7 @@ static void material_node_drivers_update(Scene *scene, bNodeTree *ntree, float c
 			/* TODO: prevent infinite recursion here... */
 			material_drivers_update(scene, (Material *)node->id, ctime);
 		}
-		else if (node->type == NODE_GROUP) {
+		else if (node->type == NODE_GROUP && node->id) {
 			material_node_drivers_update(scene, (bNodeTree *)node->id, ctime);
 		}
 	}