The launch of the open-source GameCube and Wii emulator Dolphin on Steam has been blocked by a Digital Copyright Act (DMCA) complaint filed by Nintendo against Valve.

Legal Notice, PC Gamer reports, was dated May 26, 2023, and addressed to Valve’s legal department. The document claims that the Dolphin emulator violates Nintendo’s intellectual property rights and should therefore be removed from the Steam store.

Such DMCA notices are typically sent to service providers, such as Valve, who must notify the alleged infringer. The Dolphin development team now has the option to file a counter-notice with Valve if they dispute Nintendo’s claims or comply with takedown requests. If Dolphin decides to file a counter-notice, Nintendo will have approximately two weeks to decide whether to file a lawsuit.

The consequences of the legal process, in this case, will be far-reaching for the entire market. If Nintendo wins the case, most, if not all, emulators of modern game systems could be blocked due to DMCA violations. On the opposite, a favorable verdict for Dolphin could completely free the hands of the emulator community.

In the past, courts have heard similar lawsuits from Sony against Bleem! and Connectix, related to game emulation, in which it was decided that emulators’ use of PlayStation BIOS and firmware did not infringe copyright. These decisions are often cited to legitimize emulation in the United States. However, Nintendo’s case, based on other legal grounds, complicates the situation.

The DCMA notice sent by Nintendo to Valve uses copyright circumvention language, alleging that the Dolphin emulator uses unauthorized cryptographic keys to decrypt just before or during the game launch. Thus, the use of the Dolphin emulator allegedly illegally “circumvent[s] a technological measure that effectively controls access to a work protected under’ the Copyright Act.”

Despite being banned from publishing on Steam for now, Dolphin remains available on its Github page and official website. As reported on the emulator’s blog, the Steam release has been delayed indefinitely as the team explores options.