diff --git a/Orange/widgets/unsupervised/owlouvainclustering.py b/Orange/widgets/unsupervised/owlouvainclustering.py
index 2bd4c923e90..10738c4252e 100644
--- a/Orange/widgets/unsupervised/owlouvainclustering.py
+++ b/Orange/widgets/unsupervised/owlouvainclustering.py
@@ -265,8 +265,7 @@ def commit(self):
 
         # Prepare callbacks
         queue.on_progress.connect(lambda val: self.progressBarSet(100 * val))
-        queue.on_complete.connect(self._processing_complete)
-        queue.on_complete.connect(self._send_data)
+        queue.on_complete.connect(self._on_complete)
         queue.on_exception.connect(self._handle_exceptions)
         self.__queue = queue
 
@@ -275,6 +274,10 @@ def commit(self):
         self.setBlocking(True)
         self.__future = self.__executor.submit(queue.start)
 
+    def _on_complete(self):
+        self._processing_complete()
+        self._send_data()
+
     def _send_data(self):
         if self.partition is None or self.data is None:
             return