diff --git a/NetworkPrinterOutputDevice.py b/NetworkPrinterOutputDevice.py
index f17ea99143..21a5e14672 100644
--- a/NetworkPrinterOutputDevice.py
+++ b/NetworkPrinterOutputDevice.py
@@ -65,7 +65,6 @@ class NetworkPrinterOutputDevice(PrinterOutputDevice):
                     self.setProgress(print_job_reply.json()["progress"])
                 else:
                     self.setProgress(0)
-
                 
             except Exception as e:
                 self.setConnectionState(ConnectionState.error)
@@ -86,8 +85,9 @@ class NetworkPrinterOutputDevice(PrinterOutputDevice):
 
     def close(self):
         self._connection_state == ConnectionState.closed
-        self._update_thread.join()
-        self._update_thread = None
+        if self._update_thread != None:
+            self._update_thread.join()
+            self._update_thread = None
 
     def requestWrite(self, node, file_name = None, filter_by_machine = False):
         self._file = getattr(Application.getInstance().getController().getScene(), "gcode_list")