diff --git a/cura/Machines/MachineErrorChecker.py b/cura/Machines/MachineErrorChecker.py
index 857f0bc1c4..964331909c 100644
--- a/cura/Machines/MachineErrorChecker.py
+++ b/cura/Machines/MachineErrorChecker.py
@@ -127,7 +127,7 @@ class MachineErrorChecker(QObject):
 
         # Populate the (stack, key) tuples to check
         self._stacks_and_keys_to_check = deque()
-        for stack in [global_stack] + list(global_stack.extruders.values()):
+        for stack in global_stack.extruders.values():
             for key in stack.getAllKeys():
                 self._stacks_and_keys_to_check.append((stack, key))