diff --git a/dragonflow/switch/drivers/ovs/datapath.py b/dragonflow/switch/drivers/ovs/datapath.py
index e5d228784..46b3623c5 100644
--- a/dragonflow/switch/drivers/ovs/datapath.py
+++ b/dragonflow/switch/drivers/ovs/datapath.py
@@ -78,6 +78,7 @@ class Datapath(object):
         Instantiate the applications (Including table and register allocation)
         Wire the applications (including translating registers)
         """
+        self.clear_old_set_up()
         self._dp = os_ken_base.datapath
         self._table_generator = _sequence_generator(
             cfg.CONF.df.datapath_autoalloc_table_offset)
@@ -121,6 +122,13 @@ class Datapath(object):
         for edge in self._layout.edges:
             self._install_edge(edge)
 
+    def clear_old_set_up(self):
+        if self.apps:
+            for name, app in self.apps.items():
+                dp_alloc = self._dp_allocs[name]
+                for state_name, table_num in dp_alloc.states.items():
+                    app.api.unregister_table_handler(table_num)
+
     def _get_app_class(self, app_type):
         """Get an application class (Python class) by app name"""
         mgr = stevedore.NamedExtensionManager(
diff --git a/dragonflow/switch/drivers/ovs/os_ken_base_app.py b/dragonflow/switch/drivers/ovs/os_ken_base_app.py
index 93d6d8ac8..232988660 100644
--- a/dragonflow/switch/drivers/ovs/os_ken_base_app.py
+++ b/dragonflow/switch/drivers/ovs/os_ken_base_app.py
@@ -87,7 +87,7 @@ class OsKenDFAdapter(ofp_handler.OFPHandler):
             )
         self.table_handlers[table_id] = handler
 
-    def unregister_table_handler(self, table_id, handler):
+    def unregister_table_handler(self, table_id):
         self.table_handlers.pop(table_id, None)
 
     def notify_switch_sync_finished(self):