diff --git a/distrib/builder/event.py b/distrib/builder/event.py
index a9dd38d04c..91d281c6c8 100644
--- a/distrib/builder/event.py
+++ b/distrib/builder/event.py
@@ -124,7 +124,7 @@ def version_from_filename(self, name):
 
     def extract_version_from_filename(self, name):
         if '_osx' in name:
-            pos = name.find('_osx') + 6
+            pos = name.find('_osx') + 4
         else:
             pos = 0
         pos = name.find('_', pos)