def get_short_path_name(long_name):
    """
    Gets the short path name of a given long path.
    http://stackoverflow.com/a/23598461/200291
    """
output_buf_size = 0
while True:
    output_buf = ctypes.create_unicode_buffer(output_buf_size)
needed = _GetShortPathNameW(long_name, output_buf, output_buf_size)
if output_buf_size >= needed:
    return output_buf.value
else:
    output_buf_size = needed
Как получить короткое имя файла Windows в python?