diff --git a/virtualenv.py b/virtualenv.py

index 1d46506..68284f6 100755

--- a/virtualenv.py

+++ b/virtualenv.py

@@ -860,7 +860,10 @@ def install_wheel(project_names, py_executable, search_dirs=None,

         import pip

-        cert_data = pkgutil.get_data("pip._vendor.requests", "cacert.pem")

+        try:

+            cert_data = pkgutil.get_data("pip._vendor.requests", "cacert.pem")

+        except IOError:

+            cert_data = None

         if cert_data is not None:

             cert_file = tempfile.NamedTemporaryFile(delete=False)

             cert_file.write(cert_data)