diff --git a/src/quickfix.c b/src/quickfix.c
index c67397a..7ff4318 100644
--- a/src/quickfix.c
+++ b/src/quickfix.c
@@ -2125,6 +2125,7 @@
 	--qi->qf_lists[idx].qf_count;
     }
     vim_free(qi->qf_lists[idx].qf_title);
+    qi->qf_lists[idx].qf_title = NULL;
 }
 
 /*