diff --git a/plugins/GCodeReader/FlavorParser.py b/plugins/GCodeReader/FlavorParser.py
index 05f40b41e7..ead527a61f 100644
--- a/plugins/GCodeReader/FlavorParser.py
+++ b/plugins/GCodeReader/FlavorParser.py
@@ -286,7 +286,9 @@ class FlavorParser:
         self._cancelled = False
         # We obtain the filament diameter from the selected extruder to calculate line widths
         global_stack = CuraApplication.getInstance().getGlobalContainerStack()
-        self._filament_diameter = global_stack.extruders[str(self._extruder_number)].getProperty("material_diameter", "value")
+
+        if global_stack:
+            self._filament_diameter = global_stack.extruders[str(self._extruder_number)].getProperty("material_diameter", "value")
 
         scene_node = CuraSceneNode()