diff --git a/src/saveload/ai_sl.cpp b/src/saveload/ai_sl.cpp
--- a/src/saveload/ai_sl.cpp
+++ b/src/saveload/ai_sl.cpp
@@ -102,5 +102,5 @@ static void Save_AIPL()
 }
 
 extern const ChunkHandler _ai_chunk_handlers[] = {
-	{ 'AIPL', Save_AIPL, Load_AIPL, CH_ARRAY | CH_LAST},
+	{ 'AIPL', Save_AIPL, Load_AIPL, NULL, CH_ARRAY | CH_LAST},
 };