Mutagen throws error when reading .flac file

Question

I have coded this script to read the metadata from a FLAC file, sometimes it works, but sometimes throws this error and don't know why. These files are not damaged. Seems that it has trouble reading the header of certain FLAC files, but I don't know how to get around this.

This is the code:

def get_meta():
    for dirpath, directories, files in os.walk(XPATH):
        for sound_file in files:
            date = artist = album = title = genre = ""
            if sound_file.endswith('.flac'):
                print('Flac file found, getting metadata and renaming...')
                flac_file = os.path.join(dirpath, sound_file)
                from mutagen.flac import FLAC
                metadata = mutagen.flac.Open(flac_file)



File "recursivetest.py", line 54, in get_sound
    metadata = mutagen.flac.Open(flac_file)
  File "/home/xavier/Code/autotube/venv/lib/python3.5/site-packages/mutagen/_file.py", line 42, in __init__
    self.load(filename, *args, **kwargs)
  File "/home/xavier/Code/auto/venv/lib/python3.5/site-packages/mutagen/flac.py", line 759, in load
    self.__check_header(fileobj)
  File "/home/xavier/Code/auto/venv/lib/python3.5/site-packages/mutagen/flac.py", line 857, in __check_header
    header = fileobj.read(4)
  File "/home/xavier/Code/auto/venv/lib/python3.5/site-packages/mutagen/flac.py", line 68, in read
    size, len(data)))
mutagen.flac.error: file said 4 bytes, read 0 bytes