diff --git a/mcxlab/mcxlab.m b/mcxlab/mcxlab.m
index 8a1b4203..05a4c553 100644
--- a/mcxlab/mcxlab.m
+++ b/mcxlab/mcxlab.m
@@ -560,6 +560,8 @@
             flags = {cfg(i).savedetflag};
             if (isfield(cfg(i), 'issaveref'))
                 flags{end + 1} = cfg(i).issaveref;
+            else
+                flags{end + 1} = 0;
             end
             if (isfield(cfg(i), 'srcnum'))
                 flags{end + 1} = cfg(i).srcnum;