diff --git a/src/game_tab/HalfMove.cpp b/src/game_tab/HalfMove.cpp
index ae63527..32924e1 100644
--- a/src/game_tab/HalfMove.cpp
+++ b/src/game_tab/HalfMove.cpp
@@ -193,6 +193,8 @@ bool HalfMove::HasParent(HalfMove*m){
 }
 
 bool HalfMove::HasChild(HalfMove*m){
+  if(m==nullptr)
+    return false;
   if(mainline==m){
     return true;
   }