One of the world's largest hard disk manufacturers has blocked its customers from sharing online their media files that are stored on networked drives.
Western Digital says the decision to block sharing of music and audio files is an anti-piracy effort.
The ban operates regardless of whether the files are copy-protected, or a user's own home-produced content.
Digital activists say it is the latest step in a so-called war on copyright theft that is damaging consumer rights.
The shift to a digital world in which all forms of content, from books, music, and TV programmes to films, can be shared effortlessly around the world between people with an internet connection has produced an unprecedented upheaval in attitudes to media, copyright and consumer rights.