diff --git a/PyLoT.py b/PyLoT.py
index edb6a9a2..354634f9 100755
--- a/PyLoT.py
+++ b/PyLoT.py
@@ -3511,6 +3511,9 @@ class MainWindow(QMainWindow):
             self.project = Project.load(fnm)
             if hasattr(self.project, 'parameter'):
                 if self.project.parameter:
+                    # do this step to update default parameter on older PyLoT projects
+                    self.project.parameter.reinit_default_parameters()
+
                     self._inputs = self.project.parameter
                     self.updateFilteroptions()
             # added for backwards compatibility with older events not having a 'dirty' attribute
diff --git a/pylot/core/io/inputs.py b/pylot/core/io/inputs.py
index 1e8effd0..6f2528bd 100644
--- a/pylot/core/io/inputs.py
+++ b/pylot/core/io/inputs.py
@@ -194,6 +194,9 @@ class PylotParameter(object):
         all_names += self.get_special_para_names()['quality']
         return all_names
 
+    def reinit_default_parameters(self):
+        self.__init_default_paras()
+
     @staticmethod
     def check_range(value, max_value, min_value):
         """