diff --git a/PVE/QemuServer/Cloudinit.pm b/PVE/QemuServer/Cloudinit.pm
index 609e8394..ab001f99 100644
--- a/PVE/QemuServer/Cloudinit.pm
+++ b/PVE/QemuServer/Cloudinit.pm
@@ -49,7 +49,7 @@ sub commit_cloudinit_disk {
     }
 
     eval {
-	run_command([['genisoimage', '-R', '-V', $label, $path],
+	run_command([['genisoimage', '-iso-level', '3', '-R', '-V', $label, $path],
 		     ['qemu-img', 'dd', '-n', '-f', 'raw', '-O', $format,
 		      'isize=0', "osize=$size", "of=$iso_path"]]);
     };