Поврежденные файлы или что это?

Помог вот этот способ.

Manually disable locking state:

  • put Nextcloud in maintenance mode: edit config/config.php and change this line:
    'maintenance' => true,
  • Empty table oc_file_locks : Use tools such as phpmyadmin or connect directly to your database and run (the default table prefix is oc_ , this prefix can be different or even empty):
    DELETE FROM oc_file_locks WHERE 1
  • disable maintenance mode (undo first step).
  • Make sure your cron-jobs run properly (you admin page tells you when cron ran the last time): https://docs.nextcloud.org/server/13/admin_manual/configuration_server/background_jobs_configuration.html

Вот ссылка на тему вдруг интересно все почитать.