diff --git a/mlair/run_modules/post_processing.py b/mlair/run_modules/post_processing.py
index 3b9b563426a80816f7cf1ea9e114a8395d9fbba0..73aebb008ebf1f61eb2878293fc160cf549d19cb 100644
--- a/mlair/run_modules/post_processing.py
+++ b/mlair/run_modules/post_processing.py
@@ -306,7 +306,7 @@ class PostProcessing(RunEnvironment):
         try:
             if ("filter" in self.test_data[0].get_X(as_numpy=False)[0].coords) and (
                     "PlotSeparationOfScales" in plot_list):
-                filter_dim = self.data_store.get("filter_dim", None)
+                filter_dim = self.data_store.get_default("filter_dim", None)
                 PlotSeparationOfScales(self.test_data, plot_folder=self.plot_path, time_dim=time_dim,
                                        window_dim=window_dim, target_dim=target_dim, **{"filter_dim": filter_dim})
         except Exception as e: