diff --git a/i_scene_cp77_gltf/exporters/glb_export.py b/i_scene_cp77_gltf/exporters/glb_export.py
index 16b5d6f..037d366 100644
--- a/i_scene_cp77_gltf/exporters/glb_export.py
+++ b/i_scene_cp77_gltf/exporters/glb_export.py
@@ -191,7 +191,7 @@ def export_meshes(context, filepath, export_visible, limit_selected, static_prop
             return {'CANCELLED'}
 
         for shapekey in mesh.data.shape_keys.key_blocks:
-            if(shapekey.tag == False):
+            if(shapekey.id_data.tag == False):
                 show_message("Custom Shapekeys detected! Please remove them before exporting.")
                 return {'CANCELLED'}
             
diff --git a/i_scene_cp77_gltf/importers/import_with_materials.py b/i_scene_cp77_gltf/importers/import_with_materials.py
index 68a56f3..d03d271 100644
--- a/i_scene_cp77_gltf/importers/import_with_materials.py
+++ b/i_scene_cp77_gltf/importers/import_with_materials.py
@@ -196,7 +196,7 @@ def CP77GLBimport(self, with_materials, remap_depot, exclude_unused_mats=True, i
         if obj not in bpy.data.meshes.keys():
             continue
         for shapekey in bpy.data.meshes[obj].shape_keys.key_blocks:
-            shapekey.tag = True
+            shapekey.id_data.tag = True
          
 
     if not cp77_addon_prefs.non_verbose: