diff --git a/mingw-w64-crt/testcases/t_btowc.c b/mingw-w64-crt/testcases/t_btowc.c
index 7adcedd..8137a82 100644
--- a/mingw-w64-crt/testcases/t_btowc.c
+++ b/mingw-w64-crt/testcases/t_btowc.c
@@ -36,7 +36,7 @@
   /**
    * Test SBCS code page
    */
-  assert (setlocale (LC_ALL, "English_United States.ACP") != NULL);
+  assert (setlocale (LC_ALL, "English_United States.1252") != NULL);
   assert (MB_CUR_MAX == 1);
 
   /**
@@ -56,7 +56,7 @@
   /**
    * Test DBCS code page
    */
-  assert (setlocale (LC_ALL, "Japanese_Japan.ACP") != NULL);
+  assert (setlocale (LC_ALL, "Japanese_Japan.932") != NULL);
   assert (MB_CUR_MAX == 2);
 
   /**
diff --git a/mingw-w64-crt/testcases/t_mbrlen.c b/mingw-w64-crt/testcases/t_mbrlen.c
index b66e277..62051d6 100644
--- a/mingw-w64-crt/testcases/t_mbrlen.c
+++ b/mingw-w64-crt/testcases/t_mbrlen.c
@@ -73,7 +73,7 @@
   /**
    * Test SBCS code page
    */
-  assert (setlocale (LC_ALL, "English_United States.ACP") != NULL);
+  assert (setlocale (LC_ALL, "English_United States.1252") != NULL);
   assert (MB_CUR_MAX == 1);
 
   /**
@@ -92,7 +92,7 @@
   /**
    * Test DBCS code page
    */
-  assert (setlocale (LC_ALL, "Japanese_Japan.ACP") != NULL);
+  assert (setlocale (LC_ALL, "Japanese_Japan.932") != NULL);
   assert (MB_CUR_MAX == 2);
 
   /**
diff --git a/mingw-w64-crt/testcases/t_mbrtowc.c b/mingw-w64-crt/testcases/t_mbrtowc.c
index e37986d..0e58946 100644
--- a/mingw-w64-crt/testcases/t_mbrtowc.c
+++ b/mingw-w64-crt/testcases/t_mbrtowc.c
@@ -104,7 +104,7 @@
   /**
    * Test DBCS code page
    */
-  assert (setlocale (LC_ALL, "Japanese_Japan.ACP") != NULL);
+  assert (setlocale (LC_ALL, "Japanese_Japan.932") != NULL);
   assert (MB_CUR_MAX == 2);
 
   /**
diff --git a/mingw-w64-crt/testcases/t_mbsrtowcs.c b/mingw-w64-crt/testcases/t_mbsrtowcs.c
index 9cfd9c9..d53103f 100644
--- a/mingw-w64-crt/testcases/t_mbsrtowcs.c
+++ b/mingw-w64-crt/testcases/t_mbsrtowcs.c
@@ -134,7 +134,7 @@
   /**
    * Test SBCS code page
    */
-  assert (setlocale (LC_ALL, "English_United States.ACP") != NULL);
+  assert (setlocale (LC_ALL, "English_United States.1252") != NULL);
   assert (MB_CUR_MAX == 1);
 
   /* Test SBCS input */
@@ -196,7 +196,7 @@
   /**
    * Test DBCS code page
    */
-  assert (setlocale (LC_ALL, "Japanese_Japan.ACP") != NULL);
+  assert (setlocale (LC_ALL, "Japanese_Japan.932") != NULL);
   assert (MB_CUR_MAX == 2);
 
   /* Test ASCII input */
diff --git a/mingw-w64-crt/testcases/t_wcrtomb.c b/mingw-w64-crt/testcases/t_wcrtomb.c
index 83a89d9..d6e7c05 100644
--- a/mingw-w64-crt/testcases/t_wcrtomb.c
+++ b/mingw-w64-crt/testcases/t_wcrtomb.c
@@ -152,7 +152,7 @@
   /**
    * Test DBCS code page
    */
-  assert (setlocale (LC_ALL, "Japanese_Japan.ACP") != NULL);
+  assert (setlocale (LC_ALL, "Japanese_Japan.932") != NULL);
   assert (MB_CUR_MAX == 2);
 
   /**
diff --git a/mingw-w64-crt/testcases/t_wcsrtombs.c b/mingw-w64-crt/testcases/t_wcsrtombs.c
index b5f744f..87fbe96 100644
--- a/mingw-w64-crt/testcases/t_wcsrtombs.c
+++ b/mingw-w64-crt/testcases/t_wcsrtombs.c
@@ -191,7 +191,7 @@
   /**
    * Test SBCS code page
    */
-  assert (setlocale (LC_ALL, "English_United States.ACP") != NULL);
+  assert (setlocale (LC_ALL, "English_United States.1252") != NULL);
   assert (MB_CUR_MAX == 1);
 
   /* Test ASCII input */
@@ -354,7 +354,7 @@
   /**
    * Test DBCS code page
    */
-  assert (setlocale (LC_ALL, "Japanese_Japan.ACP") != NULL);
+  assert (setlocale (LC_ALL, "Japanese_Japan.932") != NULL);
   assert (MB_CUR_MAX == 2);
 
   /* Test ASCII input */
diff --git a/mingw-w64-crt/testcases/t_wctob.c b/mingw-w64-crt/testcases/t_wctob.c
index 6177223..a89064b 100644
--- a/mingw-w64-crt/testcases/t_wctob.c
+++ b/mingw-w64-crt/testcases/t_wctob.c
@@ -65,7 +65,7 @@
   /**
    * Test DBCS code page
    */
-  assert (setlocale (LC_ALL, "Japanese_Japan.ACP") != NULL);
+  assert (setlocale (LC_ALL, "Japanese_Japan.932") != NULL);
   assert (MB_CUR_MAX == 2);
 
   /**