diff --git a/minimp3_ex.h b/minimp3_ex.h
index 2871705..e8bf445 100644
--- a/minimp3_ex.h
+++ b/minimp3_ex.h
@@ -1173,7 +1173,7 @@ static int mp3dec_open_file_h(HANDLE file, mp3dec_map_info_t *map_info)
 
     HANDLE mapping = NULL;
     LARGE_INTEGER s;
-    s.LowPart = GetFileSize(file, (DWORD*)&s.HighPart);
+    s.LowPart = GetFileSizeEx(file, &s);
     if (s.LowPart == INVALID_FILE_SIZE && GetLastError() != NO_ERROR)
         goto error;
     map_info->size = s.QuadPart;
@@ -1193,12 +1193,28 @@ static int mp3dec_open_file_h(HANDLE file, mp3dec_map_info_t *map_info)
     CloseHandle(file);
     return MP3D_E_IOERROR;
 }
-
+#if !defined(WINAPI_FAMILY) || WINAPI_FAMILY == WINAPI_FAMILY_DESKTOP_APP
+#define __mp3dec_create_file(path, omode, smode, cflags) CreateFileW(path, omode, smode, nullptr, cflags, 0, nullptr)
+#else
+#define __mp3dec_create_file(path, omode, smode, cflags) CreateFile2(path, omode, smode, cflags, nullptr)
+#endif
 static int mp3dec_open_file(const char *file_name, mp3dec_map_info_t *map_info)
 {
     if (!file_name)
         return MP3D_E_PARAM;
-    HANDLE file = CreateFileA(file_name, GENERIC_READ, FILE_SHARE_READ, 0, OPEN_EXISTING, 0, 0);
+    int cch = ::MultiByteToWideChar(CP_UTF8, 0, file_name, -1, NULL, 0);
+    if (cch < 2)
+        return MP3D_E_PARAM;
+    wchar_t* file_name_w = (wchar_t*)malloc(cch * sizeof(wchar_t*));
+    if (!file_name_w)
+        return MP3D_E_MEMORY;
+    if (::MultiByteToWideChar(CP_UTF8, 0, file_name, cch, file_name_w, cch) != cch)
+    {
+        free(file_name_w);
+        return MP3D_E_PARAM;
+    }
+    HANDLE file = __mp3dec_create_file(file_name_w, GENERIC_READ, FILE_SHARE_READ, OPEN_EXISTING);
+    free(file_name_w);
     if (INVALID_HANDLE_VALUE == file)
         return MP3D_E_IOERROR;
     return mp3dec_open_file_h(file, map_info);
@@ -1208,7 +1224,7 @@ static int mp3dec_open_file_w(const wchar_t *file_name, mp3dec_map_info_t *map_i
 {
     if (!file_name)
         return MP3D_E_PARAM;
-    HANDLE file = CreateFileW(file_name, GENERIC_READ, FILE_SHARE_READ, 0, OPEN_EXISTING, 0, 0);
+    HANDLE file = __mp3dec_create_file(file_name, GENERIC_READ, FILE_SHARE_READ, OPEN_EXISTING);
     if (INVALID_HANDLE_VALUE == file)
         return MP3D_E_IOERROR;
     return mp3dec_open_file_h(file, map_info);