According to Dolphin's developers, Nintendo compelled Valve to remove the emulator from Steam, citing infringement of their intellectual property rights.
According to developers of the GameCube and Wii emulator Dolphin, Valve has removed the emulator's Steam listing after receiving a cease and desist notice from Nintendo.
On May 27, the developers of Dolphin announced that the Steam port of the emulator would be "indefinitely postponed" after Valve removed the listing.
"It is with much disappointment that we have to announce that the Dolphin on Steam release has been indefinitely postponed," the developers wrote on Dolphin's website. "We were notified by Valve that Nintendo has issued a cease and desist citing the DMCA against Dolphin's Steam page, and have removed Dolphin from Steam until the matter is settled."
Nintendo alleges, as stated in a copy of legal notice reviewed by PC Gamer, that the emulator's operation involves the unauthorized utilization of specific cryptographic keys and "decrypting the ROMs at or immediately before runtime."
Although emulation itself is legal, enabling users to bypass protections on game ROMs may potentially infringe on Nintendo's intellectual property rights.
In a statement to Kotaku, a representative from Nintendo addressed the situation, saying that Nintendo is dedicated to "protecting the hard work and creativity of video game engineers and developers."
"This emulator illegally circumvents Nintendo’s protection measures and runs illegal copies of games," they continued. "Using illegal emulators or illegal copies of games harms development and ultimately stifles innovation. Nintendo respects the intellectual property rights of other companies, and in turn expects others to do the same."
There seems to be an increase in Nintendo's efforts to combat emulation. The team behind the Skyline Nintendo Switch emulator for Android devices recently discontinued their work on the project, citing potential legal risks. Additionally, GitHub removed the repository for Lockpick RCM, a software enabling users to extract their own Switch's security keys for emulation programs, in response to a DMCA notice.