diff --git a/xkb/xkbUtils.c b/xkb/xkbUtils.c
index dd089c204..3f5791a18 100644
--- a/xkb/xkbUtils.c
+++ b/xkb/xkbUtils.c
@@ -1326,6 +1326,7 @@ _XkbCopyNames(XkbDescPtr src, XkbDescPtr dst)
         }
         else {
             free(dst->names->radio_groups);
+            dst->names->radio_groups = NULL;
         }
         dst->names->num_rg = src->names->num_rg;