diff --git a/src/0_prepare.sh b/src/0_prepare.sh
index 78520b271..8fda1643f 100644
--- a/src/0_prepare.sh
+++ b/src/0_prepare.sh
@@ -3,3 +3,5 @@
 rm -rf work
 mkdir work
 
+# -p stops errors if the director already exists
+mkdir -p source