diff --git a/local-tool/server/scripts/kneron_bridge.py b/local-tool/server/scripts/kneron_bridge.py
index 0e2120b..4f4bd95 100644
--- a/local-tool/server/scripts/kneron_bridge.py
+++ b/local-tool/server/scripts/kneron_bridge.py
@@ -1112,5 +1112,26 @@ def main():
             _respond({"error": str(e)})
 
 
+def _cleanup():
+    """Explicitly disconnect and clear _device_group before Python GC runs.
+
+    KneronPLUS SDK's DeviceGroup.__del__ calls kp_disconnect_devices on a
+    native handle that may already be freed when the interpreter is shutting
+    down, causing 'OSError: access violation reading 0x00...'.  By doing a
+    clean disconnect + setting the global to None here, __del__ becomes a
+    no-op (None has no __del__).
+    """
+    global _device_group
+    if _device_group is not None:
+        try:
+            kp.core.disconnect_devices(_device_group)
+        except Exception:
+            pass
+        _device_group = None
+
+
 if __name__ == "__main__":
+    import atexit
+    atexit.register(_cleanup)
     main()
+    _cleanup()  # also call synchronously in case atexit doesn't fire