--- a/UI/Previewers/PreviewerHTML.py	Sat May 07 15:57:34 2016 +0200
+++ b/UI/Previewers/PreviewerHTML.py	Sun May 08 11:45:55 2016 +0200
@@ -10,8 +10,9 @@
 from __future__ import unicode_literals
 
 try:  # Only for Py2
+    basestring
     import StringIO as io   # __IGNORE_EXCEPTION__
-except ImportError:
+except (ImportError, NameError):
     import io       # __IGNORE_WARNING__
 
 import os