diff --git a/slave_scripts/copy-venv.sh b/slave_scripts/copy-venv.sh
index 69aaa203..4ee8c6f7 100755
--- a/slave_scripts/copy-venv.sh
+++ b/slave_scripts/copy-venv.sh
@@ -9,6 +9,8 @@ rm -fr jenkins_venvs
 tar xfz venv.tgz
 rm venv.tgz
 if [ -f .cache.bundle ] ; then
+  rm -rf .venv
+  virtualenv --no-site-packages .venv
   pip install --upgrade -E .venv file://`pwd`/.cache.bundle
   rm .cache.bundle
 else