diff --git a/HISTORY b/HISTORY
index f291518..421eb41 100755
--- a/HISTORY
+++ b/HISTORY
@@ -1,3 +1,6 @@
+Apr. 18 2016
+Fixed an invalid iterator issue with ranged list
+
 Apr. 15 2016
 Added some error raising when met incomplete routine or class
 
diff --git a/core/my_basic.c b/core/my_basic.c
index 20e6e3e..f6289ed 100755
--- a/core/my_basic.c
+++ b/core/my_basic.c
@@ -6404,6 +6404,12 @@ static _list_it_t* _move_list_it_next(_list_it_t* it) {
 	if(!it || !it->list || !it->list->list || (!it->curr.node && !it->list->range_begin))
 		goto _exit;
 
+	if(it->list->lock < 0) {
+		result = it;
+
+		goto _exit;
+	}
+
 	if(it->list->range_begin) {
 		if(it->list->lock)
 			it->curr.ranging += sgn(it->list->count);