diff --git a/src/validationinterface.h b/src/validationinterface.h
--- a/src/validationinterface.h
+++ b/src/validationinterface.h
@@ -17,7 +17,6 @@
 class CBlock;
 class CBlockIndex;
 struct CBlockLocator;
-class CBlockIndex;
 class CConnman;
 class CValidationInterface;
 class uint256;