Microsoft has backed “Fortnite” video game maker Epic Games in its legal battle with Apple – alleging in a new court filing that the Tim Cook-led tech giant has “stymied” its own efforts to create an Xbox mobile store.

In an email to BI after Fortnite went live on the US App Store, CEO Tim Sweeney said Epic's investment in its legal battle with Apple was worth it.

Microsoft filed an amicus brief supporting Epic Games' fight against Apple over its control over the App Store.

Apple's actions to fight the injunction from its Epic Games App Store legal fight interfered with plans to launch the Xbox mobile web store, Microsoft has said.

Just over one year ago, Xbox president Sarah Bond confirmed that Microsoft would launch its Xbox mobile store in July 2024. But as of May 2025, no such store has been launched. The delay is due to Apple, according to a recent Microsoft filing.

Microsoft says Apple's App Store rules are to blame for the continued delay of the Xbox mobile app store it announced last summer. In an amicus brief filed this week first spotted by The Verge, Microsoft expressed support for Epic Games in the company's long-running bout against Apple.