diff --git a/sulfur/src/sulfur/entropyapi.py b/sulfur/src/sulfur/entropyapi.py
index b64ea5b30..eb8f2a101 100644
--- a/sulfur/src/sulfur/entropyapi.py
+++ b/sulfur/src/sulfur/entropyapi.py
@@ -457,6 +457,13 @@ class GuiUrlFetcher(UrlFetcher):
     _use_progress_bar = True
     progress = None
 
+    def __init__(self, *args, **kwargs):
+        UrlFetcher.__init__(self, *args, **kwargs)
+        self.__average = 0.0
+        self.__downloadedsize = 0
+        self.__remotesize = 0
+        self.__datatransfer = 0
+
     @staticmethod
     def enable_progress_bar(enable):
         GuiUrlFetcher._use_progress_bar = enable