Microsoft investigates Windows 11 update causing game crashes

Microsoft is investigating reports that its August Windows 11 security update, KB5121003, is causing significant stability issues. Gamers have reported crashes, freezes, and unexpected system reboots, particularly when playing titles such as ARC Raiders, The Finals, and MARVEL Tōkon: Fighting Souls.

Embark Studios, the developer behind several affected games, has identified a conflict involving the third-party driver file inpoutx64.sys. The studio has provided a temporary workaround for players to remove the driver via command line to restore game stability without needing to uninstall the security update, which contains over 400 critical fixes.

Separately, users are reporting issues with Microsoft Defender. Recent updates to the antivirus engine and security intelligence have caused scans—including quick, full, and offline modes—to fail or stall near completion. This issue appears to affect specific combinations of Defender engine and security intelligence versions.