diff --git a/src/windows/FSNodeWINDOWS.cxx b/src/windows/FSNodeWINDOWS.cxx
index 0fecc3e1c..c8676e542 100644
--- a/src/windows/FSNodeWINDOWS.cxx
+++ b/src/windows/FSNodeWINDOWS.cxx
@@ -18,16 +18,8 @@
 #include <cassert>
 #pragma warning( disable : 4091 )
 #include <shlobj.h>
-
-#ifdef ARRAYSIZE
-  #undef ARRAYSIZE
-#endif
-
 #include <io.h>
 #include <stdio.h>
-#include <windows.h>
-// winnt.h defines ARRAYSIZE, but we want our own one...
-#undef ARRAYSIZE
 
 // F_OK, R_OK and W_OK are not defined under MSVC, so we define them here
 // For more information on the modes used by MSVC, check:
@@ -44,6 +36,7 @@
   #define W_OK 2
 #endif
 
+#include "Windows.hxx"
 #include "FSNodeWINDOWS.hxx"
 
 /**
diff --git a/src/windows/SerialPortWINDOWS.cxx b/src/windows/SerialPortWINDOWS.cxx
index 8ec755091..a9b738c7c 100644
--- a/src/windows/SerialPortWINDOWS.cxx
+++ b/src/windows/SerialPortWINDOWS.cxx
@@ -15,8 +15,7 @@
 // this file, and for a DISCLAIMER OF ALL WARRANTIES.
 //============================================================================
 
-#include <windows.h>
-
+#include "Windows.hxx"
 #include "SerialPortWINDOWS.hxx"
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
diff --git a/src/windows/SerialPortWINDOWS.hxx b/src/windows/SerialPortWINDOWS.hxx
index 8c2215c51..1fcc2882e 100644
--- a/src/windows/SerialPortWINDOWS.hxx
+++ b/src/windows/SerialPortWINDOWS.hxx
@@ -18,8 +18,7 @@
 #ifndef SERIALPORT_WINDOWS_HXX
 #define SERIALPORT_WINDOWS_HXX
 
-#include <windows.h>
-
+#include "Windows.hxx"
 #include "SerialPort.hxx"
 
 /**
diff --git a/src/windows/Windows.hxx b/src/windows/Windows.hxx
new file mode 100644
index 000000000..3c45cfcf2
--- /dev/null
+++ b/src/windows/Windows.hxx
@@ -0,0 +1,33 @@
+//============================================================================
+//
+//   SSSS    tt          lll  lll
+//  SS  SS   tt           ll   ll
+//  SS     tttttt  eeee   ll   ll   aaaa
+//   SSSS    tt   ee  ee  ll   ll      aa
+//      SS   tt   eeeeee  ll   ll   aaaaa  --  "An Atari 2600 VCS Emulator"
+//  SS  SS   tt   ee      ll   ll  aa  aa
+//   SSSS     ttt  eeeee llll llll  aaaaa
+//
+// Copyright (c) 1995-2020 by Bradford W. Mott, Stephen Anthony
+// and the Stella Team
+//
+// See the file "License.txt" for information on usage and redistribution of
+// this file, and for a DISCLAIMER OF ALL WARRANTIES.
+//============================================================================
+
+#ifndef WINDOWS_LIB_HXX
+#define WINDOWS_LIB_HXX
+
+/*
+  Using window.h directly can cause problems, since it's a C library
+  that doesn't support namespacing, etc.
+
+  Anyone needing 'windows.h' should include this file instead.
+*/
+
+#include <windows.h>
+
+#undef MessageBox
+#undef ARRAYSIZE
+
+#endif  // WINDOWS_LIB_HXX