diff --git a/mkosi.presets/20-final/mkosi.postinst b/mkosi.presets/20-final/mkosi.postinst
index 4339d7fd22..b9a26c3163 100755
--- a/mkosi.presets/20-final/mkosi.postinst
+++ b/mkosi.presets/20-final/mkosi.postinst
@@ -1,5 +1,6 @@
 #!/bin/sh
 # SPDX-License-Identifier: LGPL-2.1-or-later
+set -e
 
 if [ "$1" = "build" ]; then
     exit 0