diff --git a/base/uk.ac.stfc.isis.ibex.e4.client.product/ibex.product b/base/uk.ac.stfc.isis.ibex.e4.client.product/ibex.product
index 5f370f65de..37a6500200 100644
--- a/base/uk.ac.stfc.isis.ibex.e4.client.product/ibex.product
+++ b/base/uk.ac.stfc.isis.ibex.e4.client.product/ibex.product
@@ -18,6 +18,7 @@
       <vmArgs>-Xms40m 
 -Xmx512m
 -Dpython.console.encoding=UTF-8
+-Dpython.import.site=false
 -XX:+CreateCoredumpOnCrash
       </vmArgs>
       <vmArgsMac>-XstartOnFirstThread -Dorg.eclipse.swt.internal.carbon.smallFonts