diff --git a/letsencrypt/scripts/main.py b/letsencrypt/scripts/main.py
index 8a548a5fc..06a277283 100755
--- a/letsencrypt/scripts/main.py
+++ b/letsencrypt/scripts/main.py
@@ -111,7 +111,7 @@ def open_file(filename):
     if not os.access(filename, os.R_OK):
         raise IOError("the file '{0}' is not readable".format(filename))
 
-    return file(filename)
+    return file(filename, 'rU')
 
 
 def rollback(config, checkpoints):