Microsoft has laid the blame for Call of Duty: Infinite Warfare's disappointing Windows 10 Store release squarely at the feet of Activision.

Copies of the game purchased on Microsoft's storefront are incapable of playing online with copies purchased on Steam, drastically reducing the number of players available for matches.

One player reported to Motherboard that they could only find two players in the game's deathmatch playlist, and rapidly received a refund from Microsoft.

It's not a bug, as Activision's own support page states plainly that players "can only play these titles with other users of Windows 10 on Windows Store."

Perplexingly, a Microsoft spokesperson told Windows Central that the company "[supports] cross-play between devices and platforms for partners who want to enable it," suggesting that Activision itself disabled cross-play for the Windows Store release, while a second source confirmed that there is no technical reason why it can't talk to the Steam version.

At time of publication, Infinite Warfare was the 37th most-played game on Steam, with a 24-hour peak of 10,968 concurrent players.

Though it debuted at #1 over its launch weekend, the game's sales have been down over 40% on its predecessor Black Ops 3, according to UK sales figures.

Call of Duty: Infinite Warfare is available now for new-gen consoles and PC.