diff --git a/a/grid_file.py b/b/grid_file.py
index 4ee1fb9..1bb58cf 100644
--- a/a/grid_file.py
+++ b/b/grid_file.py
@@ -203,7 +203,8 @@ class GridIn(object):
         self.__flush_buffer()
 
         md5 = self._coll.database.command("filemd5", self._id,
-                                          root=self._coll.name)["md5"]
+                                          root=self._coll.name,
+                                          partialOk=1)["md5"]
 
         self._file["md5"] = md5
         self._file["length"] = self._position