diff --git a/cura/Settings/MachineManager.py b/cura/Settings/MachineManager.py
index d65bbfddd9..a1d824a5da 100755
--- a/cura/Settings/MachineManager.py
+++ b/cura/Settings/MachineManager.py
@@ -385,7 +385,9 @@ class MachineManager(QObject):
     #   \param definition_id \type{str} definition id that needs to look for
     #   \param metadata_filter \type{dict} list of metadata keys and values used for filtering
     @staticmethod
-    def getMachine(definition_id: str, metadata_filter: Dict[str, str] = None) -> Optional["GlobalStack"]:
+    def getMachine(definition_id: str, metadata_filter: Optional[Dict[str, str]] = None) -> Optional["GlobalStack"]:
+        if metadata_filter is None:
+            metadata_filter = {}
         machines = CuraContainerRegistry.getInstance().findContainerStacks(type = "machine", **metadata_filter)
         for machine in machines:
             if machine.definition.getId() == definition_id: