Change the path of your quod libet library

change_path.py

import os
import quodlibet.library

library_path = os.path.join(quodlibet.get_user_dir(), "songs")
library = quodlibet.library.init(library_path)
print(library.masked_mount_points)
print(library.unmask('/run/media/tamriel/HDD'))

for song in library:
    # before:
    # '~filename': '/run/media/tamriel/HDD/Musik/Tiamat/Clouds/03 Smell Of Incense.opus'
    # '~mountpoint': '/run/media/tamriel/HDD'
    song['~filename'] = song('~filename').replace('/run/media/tamriel/HDD', '/run/media/tamriel/Daten intern/Groß | Externe')
    song['~mountpoint'] = '/run/media/tamriel/Daten intern'
    library.changed([song])

library.save()