diff --git a/include/wine/debug.h b/include/wine/debug.h
index abde9d99451..adab5581583 100644
--- a/include/wine/debug.h
+++ b/include/wine/debug.h
@@ -186,7 +186,7 @@ static inline const char *wine_dbgstr_w( const WCHAR *s )
 static inline const char *wine_dbgstr_guid( const GUID *id )
 {
     if (!id) return "(null)";
-    if (!((INT_PTR)id >> 16)) return wine_dbg_sprintf( "<guid-0x%04x>", (INT_PTR)id & 0xffff );
+    if (!((ULONG_PTR)id >> 16)) return wine_dbg_sprintf( "<guid-0x%04lx>", (ULONG_PTR)id & 0xffff );
     return wine_dbg_sprintf( "{%08x-%04x-%04x-%02x%02x-%02x%02x%02x%02x%02x%02x}",
                              id->Data1, id->Data2, id->Data3,
                              id->Data4[0], id->Data4[1], id->Data4[2], id->Data4[3],