diff --git a/automation/scripts/build b/automation/scripts/build
index e3672a3626..797ff6d1b2 100755
--- a/automation/scripts/build
+++ b/automation/scripts/build
@@ -42,6 +42,7 @@ esac
 cfg_dir="automation/configs/${arch}"
 for cfg in `ls ${cfg_dir}`; do
     echo "Building $cfg"
+    make -j$(nproc) -C xen clean
     rm -f xen/.config
     make -C xen KBUILD_DEFCONFIG=../../../../${cfg_dir}/${cfg} XEN_CONFIG_EXPERT=y defconfig
     make -j$(nproc) -C xen XEN_CONFIG_EXPERT=y