diff --git a/plugins/CuraEngineBackend/CuraEngineBackend.py b/plugins/CuraEngineBackend/CuraEngineBackend.py
index 2aae1fff21..994966f9b7 100755
--- a/plugins/CuraEngineBackend/CuraEngineBackend.py
+++ b/plugins/CuraEngineBackend/CuraEngineBackend.py
@@ -632,7 +632,10 @@ class CuraEngineBackend(QObject, Backend):
         self.setState(BackendState.Done)
         self.processingProgress.emit(1.0)
 
-        gcode_list = self._scene.gcode_dict[self._start_slice_job_build_plate] #type: ignore #Because we generate this attribute dynamically.
+        try:
+            gcode_list = self._scene.gcode_dict[self._start_slice_job_build_plate] #type: ignore #Because we generate this attribute dynamically.
+        except KeyError:  # Can occur if the g-code has been cleared while a slice message is still arriving from the other end.
+            gcode_list = []
         for index, line in enumerate(gcode_list):
             replaced = line.replace("{print_time}", str(self._application.getPrintInformation().currentPrintTime.getDisplayString(DurationFormat.Format.ISO8601)))
             replaced = replaced.replace("{filament_amount}", str(self._application.getPrintInformation().materialLengths))