diff --git a/tools/PccsAdminTool/lib/intelsgx/pcs.py b/tools/PccsAdminTool/lib/intelsgx/pcs.py
index 9f1d2245..046c781d 100644
--- a/tools/PccsAdminTool/lib/intelsgx/pcs.py
+++ b/tools/PccsAdminTool/lib/intelsgx/pcs.py
@@ -5,8 +5,9 @@
 import binascii
 from urllib import parse
 from OpenSSL import crypto
-from pypac import PACSession
 from platform import system
+if system() == 'Windows':
+    from pypac import PACSession
 from lib.intelsgx.credential import Credentials
 from requests.adapters import HTTPAdapter
 from urllib3.util import Retry