diff --git a/position_3n_table.h b/position_3n_table.h
index da1fbd3..754b21c 100644
--- a/position_3n_table.h
+++ b/position_3n_table.h
@@ -222,6 +222,7 @@ public:
             delete workerLock[i];
         }
         Position* pos;
+        freePositionPool.close();
         while(freePositionPool.recv(pos)) {
             delete pos;
         }