diff --git a/trackeval/datasets/_base_dataset.py b/trackeval/datasets/_base_dataset.py
index 64bf9fc0..b24ce4a3 100644
--- a/trackeval/datasets/_base_dataset.py
+++ b/trackeval/datasets/_base_dataset.py
@@ -51,7 +51,7 @@ def get_name(self):
         return self.get_class_name()
 
     def get_output_fol(self, tracker):
-        return os.path.join(self.output_fol, tracker, self.output_sub_fol)
+        return os.path.join(''.join(self.output_fol), tracker, self.output_sub_fol)
 
     def get_display_name(self, tracker):
         """ Can be overwritten if the trackers name (in files) is different to how it should be displayed.