diff --git a/release/scripts/ui/buttons_data_mesh.py b/release/scripts/ui/buttons_data_mesh.py
index 76c66f7aece..3c8f655f17a 100644
--- a/release/scripts/ui/buttons_data_mesh.py
+++ b/release/scripts/ui/buttons_data_mesh.py
@@ -88,7 +88,7 @@ class DATA_PT_vertex_groups(DataButtonsPanel):
 			row = layout.row()
 			row.itemR(group, "name")
 
-		if ob.mode == 'EDIT':
+		if ob.mode == 'EDIT' and len(ob.vertex_groups) > 0:
 			row = layout.row()
 			
 			sub = row.row(align=True)
diff --git a/source/blender/editors/object/object_vgroup.c b/source/blender/editors/object/object_vgroup.c
index dd3e5969a75..0de1c79b796 100644
--- a/source/blender/editors/object/object_vgroup.c
+++ b/source/blender/editors/object/object_vgroup.c
@@ -876,6 +876,8 @@ static void vgroup_assign_verts(Object *ob, float weight)
 	int	i, done;
 
 	dg=BLI_findlink(&ob->defbase, ob->actdef-1);
+	if(!dg)
+		return;
 
 	if(ob->type == OB_MESH) {
 		Mesh *me= ob->data;