diff --git a/plugins/3MFWriter/ThreeMFWorkspaceWriter.py b/plugins/3MFWriter/ThreeMFWorkspaceWriter.py
index 8e20bdb411..ddff454516 100644
--- a/plugins/3MFWriter/ThreeMFWorkspaceWriter.py
+++ b/plugins/3MFWriter/ThreeMFWorkspaceWriter.py
@@ -25,11 +25,9 @@ USER_SETTINGS_PATH = "Cura/user-settings.json"
 class ThreeMFWorkspaceWriter(WorkspaceWriter):
     def __init__(self):
         super().__init__()
-        self._main_thread_lock = Lock()
         self._ucp_model = None
         self._is_ucp = False
 
-
     def setExportModel(self, model):
         if self._ucp_model != model:
             self._ucp_model = model