diff --git a/aria/core/WhatifProfile.py b/aria/core/WhatifProfile.py
index c5d50f6d0844affed846aa8f3272b2dbf3e4ed6f..4dfc2d14b4d9b90b63085b41ab811c9d86d30ae8 100644
--- a/aria/core/WhatifProfile.py
+++ b/aria/core/WhatifProfile.py
@@ -27,6 +27,7 @@
 """
 from __future__ import print_function
 
+import os
 import time
 
 CHECK_LIST = ['QUACHK', 'NQACHK', 'RAMCHK', 'C12CHK',