diff --git a/lib/controller/controller.py b/lib/controller/controller.py
index ad1fb47e4..8fe26f459 100755
--- a/lib/controller/controller.py
+++ b/lib/controller/controller.py
@@ -362,7 +362,7 @@ def get_output_extension(self):
         if options["output_format"] in ("plain", "simple"):
             return "txt"
 
-        return {options["output_format"]}
+        return options["output_format"]
 
     def setup_reports(self):
         """Create report file"""