diff --git a/builder/image-validate.sh b/builder/image-validate.sh
index 15896497..783ff269 100755
--- a/builder/image-validate.sh
+++ b/builder/image-validate.sh
@@ -37,7 +37,7 @@ apt-cache show openvpn
 # sudo -E sh -c 'apt-get install -y debian-goodies'
 # dpigs -H -n 100
 
-killall roscore
+killall --wait roscore
 
 echo "Move /etc/ld.so.preload back to its original position"
 mv /etc/ld.so.preload.disabled-for-build /etc/ld.so.preload