diff --git a/reactos/base/system/autochk/autochk.c b/reactos/base/system/autochk/autochk.c
index 3460a166edc..6e187d9315e 100644
--- a/reactos/base/system/autochk/autochk.c
+++ b/reactos/base/system/autochk/autochk.c
@@ -144,10 +144,10 @@ GetFileSystem(
 }
 
 // This is based on SysInternal's ChkDsk app
-static BOOLEAN CALLBACK
+static BOOLEAN NTAPI
 ChkdskCallback(
     IN CALLBACKCOMMAND Command,
-    IN DWORD Modifier,
+    IN ULONG Modifier,
     IN PVOID Argument)
 {
     PDWORD      Percent;