diff --git a/CellframeNodeDiagtool/WinDiagnostic.h b/CellframeNodeDiagtool/WinDiagnostic.h
index 74a06766edcc03c78a465418529c277208eadfa5..ba5376c625211bd6c915691e1dce033e992b75bf 100644
--- a/CellframeNodeDiagtool/WinDiagnostic.h
+++ b/CellframeNodeDiagtool/WinDiagnostic.h
@@ -4,7 +4,7 @@
 #include "AbstractDiagnostic.h"
 
 #include <windows.h>
-
+#include <tlhelp32.h>
 
 enum PLATFORM { WINNT1, WIN2K_XP1, WIN9X1, UNKNOWN1 };