diff --git a/dlls/kernel32/tests/locale.c b/dlls/kernel32/tests/locale.c
index bebd857dfa4..5760d7c9eb1 100644
--- a/dlls/kernel32/tests/locale.c
+++ b/dlls/kernel32/tests/locale.c
@@ -2964,9 +2964,9 @@ static void test_LocaleNameToLCID(void)
 
     buffer[0] = 0;
     SetLastError(0xdeadbeef);
-    lcid = pLocaleNameToLCID(LOCALE_NAME_SYSTEM_DEFAULT, 0);
-    ok(!lcid && GetLastError() == ERROR_INVALID_PARAMETER,
-       "Expected lcid == 0, got %08lx, error %ld\n", lcid, GetLastError());
+    lcid = LocaleNameToLCID(LOCALE_NAME_SYSTEM_DEFAULT, 0);
+    ok(lcid == GetSystemDefaultLCID(),
+       "Expected lcid == %08lx, got %08lx, error %ld\n", GetSystemDefaultLCID(), lcid, GetLastError());
     ret = pLCIDToLocaleName(lcid, buffer, LOCALE_NAME_MAX_LENGTH, 0);
     ok(ret > 0, "Expected ret > 0, got %d, error %ld\n", ret, GetLastError());
     trace("%08lx, %s\n", lcid, wine_dbgstr_w(buffer));
@@ -5817,10 +5817,9 @@ static void test_ResolveLocaleName(void)
         { L"zz+XX", NULL },
         { L"zz.XX", NULL },
         { LOCALE_NAME_INVARIANT, L"" },
-        { LOCALE_NAME_SYSTEM_DEFAULT, NULL },
     };
     INT i, ret;
-    WCHAR buffer[LOCALE_NAME_MAX_LENGTH];
+    WCHAR buffer[LOCALE_NAME_MAX_LENGTH], system[LOCALE_NAME_MAX_LENGTH];
 
     if (!pResolveLocaleName)
     {
@@ -5831,7 +5830,7 @@ static void test_ResolveLocaleName(void)
     {
         SetLastError( 0xdeadbeef );
         memset( buffer, 0xcc, sizeof(buffer) );
-        ret = pResolveLocaleName( tests[i].name, buffer, sizeof(buffer) );
+        ret = pResolveLocaleName( tests[i].name, buffer, ARRAY_SIZE(buffer) );
         if (tests[i].exp)
         {
             ok( !wcscmp( buffer, tests[i].exp ) || broken( tests[i].broken ),
@@ -5847,6 +5846,14 @@ static void test_ResolveLocaleName(void)
                     "%s: wrong error %lu\n", debugstr_w(tests[i].name), GetLastError() );
         }
     }
+    SetLastError( 0xdeadbeef );
+    memset( buffer, 0xcc, sizeof(buffer) );
+    ret = pResolveLocaleName( LOCALE_NAME_SYSTEM_DEFAULT, buffer, ARRAY_SIZE(buffer) );
+    ok( ret, "failed err %lu\n", GetLastError() );
+    GetSystemDefaultLocaleName( system, ARRAY_SIZE(system) );
+    ok( !wcscmp( buffer, system ), "got wrong syslocale %s / %s\n", debugstr_w(buffer), debugstr_w(system));
+    ok( ret == wcslen(system) + 1, "wrong len %u / %Iu\n", ret, wcslen(system) + 1 );
+
     SetLastError( 0xdeadbeef );
     ret = pResolveLocaleName( L"en-US", buffer, 4 );
     ok( !ret, "got %u\n", ret );
diff --git a/dlls/kernelbase/locale.c b/dlls/kernelbase/locale.c
index 44af29f163d..568f34d8979 100644
--- a/dlls/kernelbase/locale.c
+++ b/dlls/kernelbase/locale.c
@@ -648,6 +648,11 @@ static const NLS_LOCALE_DATA *get_locale_by_name( const WCHAR *name, LCID *lcid
         *lcid = user_lcid;
         return user_locale;
     }
+    if (name[0] == '!' && !compare_locale_names( name, LOCALE_NAME_SYSTEM_DEFAULT ))
+    {
+        *lcid = system_lcid;
+        return system_locale;
+    }
     if (!(entry = find_lcname_entry( name ))) return NULL;
     *lcid = entry->id;
     return get_locale_data( entry->idx );
@@ -671,6 +676,10 @@ static const struct sortguid *get_language_sort( const WCHAR *name )
         if (current_locale_sort) return current_locale_sort;
         name = locale_strings + user_locale->sname + 1;
     }
+    else if (name[0] == '!' && !compare_locale_names( name, LOCALE_NAME_SYSTEM_DEFAULT ))
+    {
+        name = locale_strings + system_locale->sname + 1;
+    }
 
     if (!(entry = find_lcname_entry( name )))
     {
diff --git a/include/winnls.h b/include/winnls.h
index 872fdcc3406..185a02a6bc4 100644
--- a/include/winnls.h
+++ b/include/winnls.h
@@ -336,9 +336,9 @@ static const WCHAR LOCALE_NAME_INVARIANT[] = { 0 };
 #endif
 
 #if defined(_MSC_VER) || defined(__MINGW32__)
-# define LOCALE_NAME_SYSTEM_DEFAULT      L"!sys-default-locale"
+# define LOCALE_NAME_SYSTEM_DEFAULT      L"!x-sys-default-locale"
 #else
-static const WCHAR LOCALE_NAME_SYSTEM_DEFAULT[] = {'!','s','y','s','-','d','e','f','a','u','l','t','-','l','o','c','a','l','e',0};
+static const WCHAR LOCALE_NAME_SYSTEM_DEFAULT[] = {'!','x','-','s','y','s','-','d','e','f','a','u','l','t','-','l','o','c','a','l','e',0};
 #endif
 
 #define LOCALE_NAME_USER_DEFAULT    NULL