diff --git a/reactos/sdk/include/ndk/rtltypes.h b/reactos/sdk/include/ndk/rtltypes.h
index c33aee47498..ad0702c7395 100644
--- a/reactos/sdk/include/ndk/rtltypes.h
+++ b/reactos/sdk/include/ndk/rtltypes.h
@@ -1102,7 +1102,7 @@ typedef struct _RTL_HEAP_INFORMATION
     ULONG NumberOfEntries;
     ULONG NumberOfPseudoTags;
     ULONG PseudoTagGranularity;
-    ULONG Reserved[4];
+    ULONG Reserved[5];
     PRTL_HEAP_TAG Tags;
     PRTL_HEAP_ENTRY Entries;
 } RTL_HEAP_INFORMATION, *PRTL_HEAP_INFORMATION;