diff --git a/exts/omni.ext.mobility_gen/omni/ext/mobility_gen/extension.py b/exts/omni.ext.mobility_gen/omni/ext/mobility_gen/extension.py
index 6c48712..dfad6d0 100644
--- a/exts/omni.ext.mobility_gen/omni/ext/mobility_gen/extension.py
+++ b/exts/omni.ext.mobility_gen/omni/ext/mobility_gen/extension.py
@@ -140,7 +140,11 @@ def on_shutdown(self):
         self.keyboard.disconnect()
         self.gamepad.disconnect()
         world = get_world()
-        world.remove_physics_callback("scenario_physics", self.on_physics)
+        if world is not None:
+            try:
+                world.remove_physics_callback("scenario_physics")
+            except Exception:
+                pass
 
     def start_new_recording(self):
         recording_name = datetime.datetime.now().isoformat()