diff --git a/src/main.h b/src/main.h
index 827aeabb..6a0d56e1 100644
--- a/src/main.h
+++ b/src/main.h
@@ -751,6 +751,7 @@ public:
     }
 
     CBlockIndex *GetNextInMainChain() const {
+        if( !IsInMainChain() ) return NULL;
         return nHeight+1 >= (int)vBlockIndexByHeight.size() ? NULL : vBlockIndexByHeight[nHeight+1];
     }