diff --git a/overviewer_core/tileset.py b/overviewer_core/tileset.py
index 41a8756..8899993 100644
--- a/overviewer_core/tileset.py
+++ b/overviewer_core/tileset.py
@@ -24,6 +24,7 @@ import functools
 import time
 import errno
 import stat
+import platform
 from collections import namedtuple
 from itertools import product, izip, chain