Grand Theft Auto 4 is no longer available to purchase through Steam, it was discovered over the weekend.
Now Rockstar has an explanation for the game's mysterious disappearance. You can blame Games For Windows Live.
"Grand Theft Auto IV was originally created for the Games For Windows Live platform," said the company in a statement.
"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."
While the store page for GTA 4 is still up on Steam, the purchase button has since been removed. The Xbox and PlayStation versions of the game can still be purchased on the respective storefronts.
Grand Theft Auto 4 was originally released on PC in 2008, one year after Microsoft first launched Games For Windows Live. Games For Windows Live was discontinued in 2014.