diff --git a/OptiScaler/nvapi/fakenvapi/util.h b/OptiScaler/nvapi/fakenvapi/util.h
index d0394dbe..4cab9e8f 100755
--- a/OptiScaler/nvapi/fakenvapi/util.h
+++ b/OptiScaler/nvapi/fakenvapi/util.h
@@ -5,7 +5,7 @@
 #include <map>
 #include <cstdint>
 #define WIN32_LEAN_AND_MEAN
-#include <Windows.h>
+#include <windows.h>
 
 void tonvss(NvAPI_ShortString nvss, std::string str);
 int get_config(const wchar_t* section, const wchar_t* key, int default_value);