A civil court on Wednesday ordered Dutch Web site Mininova to remove within three months all files on its servers that point to copyrighted works or face a fine of up to euro5 million ($7.16 million).
Mininova rivals Sweden's The Pirate Bay as the largest index of BitTorrent files, software that can be used to trade movies, music and computer games.
In Wednesday's ruling, the Utrecht District Court sided with Stichting Brein, a Dutch-based organization funded by copyright-holder groups. It said Mininova was inciting users to infringe copyrights and profiting from infringement by advertising on the site.
"The court didn't agree with Mininova's argument that it was impossible for it to find and remove torrents that point to copyrighted materials," the ruling said.
Unlike The Pirate Bay, Mininova was already removing files when it received a takedown notice from copyright holders.
But the court said that wasn't good enough, and Mininova should assume that all commercial media works are copyrighted.
"The court believes it's generally known that commercially made films, games, music and TV series are copyrighted and that these works are only copyright-free in exceptional cases," the ruling said.
Mininova said it was considering an appeal.
Founder Erik Dubbelboer said that obeying the order would mean "changing the way we do business."
"What that would mean in concrete terms, we can't say at this point," he said.