Rockstar has confirmed that the reason Grand Theft Auto IV is no longer available to purchase from Steam is its reliance on the Games for Windows Live (GFWL) platform, which it says Microsoft is “no longer supporting.” Although people who already own the game on Steam can continue to play it, the game’s “Add to Cart” button has disappeared from its Steam page, preventing users from buying a new copy.

“Grand Theft Auto IV was originally created for the Games For Windows Live platform,” a spokesperson from Rockstar told The Verge. “With Microsoft no longer supporting Games For Windows Live, it is no longer possible to generate the additional keys needed to continue selling the current version of the game. We are looking at other options for distributing GTAIV for PC and will share more information as soon as we can.”

GTAIV’s use of the Games for Windows Live platform has been causing issues for a little while now. Microsoft started winding down its PC gaming platform in 2013 with the closure of the Games for Windows Live store, but Rockstar has never fully patched the service out of its game. Although the game has continued to work, there are multiple forum posts and guides on the game’s Steam community page that explain how to overcome the hiccups the situation has created.

Rockstar isn’t the first company to have had to rip GFWL out of one of its games, but most other companies started the process in 2013 when it became clear Microsoft was moving on from the service. The Batman: Arkham games did so that year along with BioShock 2, while Bandai Namco allowed Dark Souls players to transfer their characters and save data to Steam as part of its process in 2014. 

Before Rockstar confirmed that GFWL was to blame for GTAIV’s disappearance from Steam, there was some fun speculation to be had as to why it has happened. PC Gamer noted that expiring song licensing agreements could have been to blame (they caused a similar problem for Vice City back in 2012), while others guessed that Rockstar could have been preparing to sell the game exclusively through its own launcher.