diff --git a/guisan-dev/include/guisan/opengl/openglimage.hpp b/guisan-dev/include/guisan/opengl/openglimage.hpp
index 50272c1a..91cedf0c 100644
--- a/guisan-dev/include/guisan/opengl/openglimage.hpp
+++ b/guisan-dev/include/guisan/opengl/openglimage.hpp
@@ -57,7 +57,7 @@
 #ifndef GCN_OPENGLIMAGE_HPP
 #define GCN_OPENGLIMAGE_HPP
 
-#if defined (_WIN32_)
+#if defined (_WIN32)
 #define WIN32_LEAN_AND_MEAN
 #include <windows.h>
 #if defined (DELETE)
diff --git a/guisan-dev/src/opengl/openglgraphics.cpp b/guisan-dev/src/opengl/openglgraphics.cpp
index 6c8f5da4..87b95e7a 100644
--- a/guisan-dev/src/opengl/openglgraphics.cpp
+++ b/guisan-dev/src/opengl/openglgraphics.cpp
@@ -60,7 +60,7 @@
 
 #include "guisan/opengl/openglgraphics.hpp"
 
-#if defined (_WIN32_)
+#if defined (_WIN32)
 #define WIN32_LEAN_AND_MEAN
 #include <windows.h>
 #endif
diff --git a/src/archivers/7z/7zFile.h b/src/archivers/7z/7zFile.h
index 2ac1fe1c..84538c03 100644
--- a/src/archivers/7z/7zFile.h
+++ b/src/archivers/7z/7zFile.h
@@ -4,7 +4,7 @@
 #ifndef __7Z_FILE_H
 #define __7Z_FILE_H
 
-#ifdef _WIN32_
+#ifdef _WIN32
 #define USE_WINDOWS_FILE
 #endif
 
diff --git a/src/bsdsocket.cpp b/src/bsdsocket.cpp
index bc987dd8..3e1da64a 100644
--- a/src/bsdsocket.cpp
+++ b/src/bsdsocket.cpp
@@ -1591,7 +1591,7 @@ done:
 
 static uae_u32 REGPARAM2 bsdsocklib_GetSocketEvents(TrapContext *ctx)
 {
-#ifdef _WIN32_
+#ifdef _WIN32
 	struct socketbase *sb = get_socketbase(ctx);
 	int i;
 	int flags;
diff --git a/src/filesys.cpp b/src/filesys.cpp
index b04cbce3..1131214d 100644
--- a/src/filesys.cpp
+++ b/src/filesys.cpp
@@ -7508,7 +7508,7 @@ void filesys_install_code (void)
 	afterdos_initcode = filesys_get_entry(8);
 }
 
-#ifdef _WIN32_
+#ifdef _WIN32
 #include "od-win32/win32_filesys.cpp"
 #endif
 
diff --git a/src/fsdb.cpp b/src/fsdb.cpp
index f4df4c23..f487ad07 100644
--- a/src/fsdb.cpp
+++ b/src/fsdb.cpp
@@ -41,7 +41,7 @@ TCHAR *nname_begin (TCHAR *nname)
   return nname;
 }
 
-#ifndef _WIN32_
+#ifndef _WIN32
 /* Find the name REL in directory DIRNAME.  If we find a file that
  * has exactly the same name, return REL.  If we find a file that
  * has the same name when compared case-insensitively, return a
diff --git a/src/include/bsdsocket.h b/src/include/bsdsocket.h
index b0986b2b..04fd25b8 100644
--- a/src/include/bsdsocket.h
+++ b/src/include/bsdsocket.h
@@ -29,7 +29,7 @@ extern void deinit_socket_layer (void);
 
 #define MAXADDRLEN 256
 
-#ifdef _WIN32_
+#ifdef _WIN32
 #define SOCKET_TYPE SOCKET
 #else
 #define SOCKET_TYPE int
@@ -70,7 +70,7 @@ struct socketbase {
 
     unsigned int *mtable;	/* window messages allocated for asynchronous event notification */
     /* host-specific fields below */
-#ifdef _WIN32_
+#ifdef _WIN32
     SOCKET_TYPE sockAbort;	/* for aborting WinSock2 select() (damn Microsoft) */
     SOCKET_TYPE sockAsync;	/* for aborting WSBAsyncSelect() in window message handler */
     int needAbort;		/* abort flag */
diff --git a/src/include/uae/string.h b/src/include/uae/string.h
index 8e992bbf..ab5335c1 100644
--- a/src/include/uae/string.h
+++ b/src/include/uae/string.h
@@ -7,7 +7,7 @@
 #include "uae/types.h"
 #include <string.h>
 
-#ifdef _WIN32_
+#ifdef _WIN32
 /* Make sure the real _tcs* functions are already declared before we
  * re-define them below. */
 #include <tchar.h>
@@ -15,7 +15,7 @@
 #include <stdlib.h>
 #endif
 
-#ifdef _WIN32_
+#ifdef _WIN32
 /* Using the real _tcs* functions */
 #else
 #define _istdigit isdigit
diff --git a/src/include/uae/types.h b/src/include/uae/types.h
index f188ae7d..334136ab 100644
--- a/src/include/uae/types.h
+++ b/src/include/uae/types.h
@@ -53,7 +53,7 @@ typedef uae_u32 uaecptr;
 
 typedef char uae_char;
 
-#ifdef _WIN32_
+#ifdef _WIN32
 #include <tchar.h>
 #ifdef UNICODE
 #define SIZEOF_TCHAR 2
diff --git a/src/inputdevice.cpp b/src/inputdevice.cpp
index dd30c5f1..fcdd79c4 100644
--- a/src/inputdevice.cpp
+++ b/src/inputdevice.cpp
@@ -2806,7 +2806,7 @@ static int handle_input_event(int nr, int state, int max, int autofire)
 	if (nr <= 0 || nr == INPUTEVENT_SPC_CUSTOM_EVENT)
 		return 0;
 
-#ifdef _WIN32_
+#ifdef _WIN32
 	// ignore normal GUI event if forced gui key is in use
 	if (currprefs.win32_guikey >= 0 && nr == INPUTEVENT_SPC_ENTERGUI)
 		return 0;
diff --git a/src/zfile.cpp b/src/zfile.cpp
index dc887677..b14b895f 100644
--- a/src/zfile.cpp
+++ b/src/zfile.cpp
@@ -1383,7 +1383,7 @@ static struct zfile *zfile_fopen_x (const TCHAR *name, const TCHAR *mode, int ma
   return l;
 }
 
-#ifdef _WIN32_
+#ifdef _WIN32
 static int isinternetfile (const TCHAR *name)
 {
 	if (!_tcsnicmp (name, _T("http://"), 7) || !_tcsnicmp (name, _T("https://"), 8))
@@ -1490,7 +1490,7 @@ static struct zfile *zfile_fopenx2 (const TCHAR *name, const TCHAR *mode, int ma
 	struct zfile *f;
 	TCHAR tmp[MAX_DPATH];
 
-#ifdef _WIN32_
+#ifdef _WIN32
 	if (isinternetfile (name))
 		return zfile_fopen_internet (name, mode, mask);
 #endif
diff --git a/src/zfile_archive.cpp b/src/zfile_archive.cpp
index 06de1855..35332d06 100644
--- a/src/zfile_archive.cpp
+++ b/src/zfile_archive.cpp
@@ -12,7 +12,7 @@
 
 #include "sysdeps.h"
 
-#ifdef _WIN32_
+#ifdef _WIN32
 #include <windows.h>
 #include "win32.h"
 #endif
@@ -676,7 +676,7 @@ static int canrar (void)
 
 	if (israr == 0) {
 		israr = -1;
-#ifdef _WIN32_
+#ifdef _WIN32
 		{
 			HMODULE rarlib;
 
@@ -857,7 +857,7 @@ static aapGetFileInfo aaGetFileInfo;
 static aapExtract aaExtract;
 static aapCloseArchive aaCloseArchive;
 
-#ifdef _WIN32_
+#ifdef _WIN32
 static HMODULE arcacc_mod;
 
 static void arcacc_free (void)