Valve removed a game from its Steam video game platform and store because it contained malware, according to media reports. In its notice to users who downloaded the game, Valve said affected users may want to “consider fully reformatting your operating system.”

This sort of thing is atypical for Steam. The automated systems for game updates can sometimes crash PCs when the updates are problematic, but so far Valve has done a very good job of keeping actual malware out of the Steam store. (Can’t say the same for Apple, Google, or Microsoft .)

The free-to-play game, PirateFi, infects users with malware that steals browser cookies, enabling the malware’s creator to hijack access to various online accounts.

In-game ads have now been officially banned from the popular gaming platform Steam, according to the new guidelines.

Valve has sent a warning email to users that installed removed game PirateFi on Steam, explaining that it included suspected malware.

Digital video game distributor Steam’s parent company, Valve, has removed the free-to-play game PirateFi from its Steam storefront just days after its release. This move follows word that its developer and publisher,