diff --git a/reactos/include/reactos/win32k/ntuser.h b/reactos/include/reactos/win32k/ntuser.h
index 7b47c3c2f14..48ade8ddd68 100644
--- a/reactos/include/reactos/win32k/ntuser.h
+++ b/reactos/include/reactos/win32k/ntuser.h
@@ -362,7 +362,7 @@ typedef struct _CLIENTINFO
     DWORD dwHookCurrent;
     INT cInDDEMLCallback;
     PCLIENTTHREADINFO pClientThreadInfo;
-    DWORD dwHookData;
+    ULONG_PTR dwHookData;
     DWORD dwKeyCache;
     DWORD afKeyState[2];
     DWORD dwAsyncKeyCache;