Microsoft's August 2026 update for Windows 11 (KB5121003) is causing game crashes, unexpected system reboots, and access violations across multiple titles, prompting Embark Studios to confirm the issue and Microsoft to launch an investigation after a week of gamer complaints.
The update rolled out on August 11, 2026, pushing version 25H2 systems to build 26200.9168 and version 24H2 systems to build 26100.9168. While the update addresses more than 400 security vulnerabilities and is Microsoft's latest cumulative release, the side effects for gamers have been significant and well-documented.
According to a support document spotted by Windows Latest, Microsoft acknowledges the problem but has not yet confirmed whether the update itself is the root cause. The company states: "We are presently investigating to determine if this is an issue caused by Microsoft. We will provide an update when more information is available."
Games Affected
The most prominently affected titles are ARC Raiders and The Finals, both developed by Embark Studios, along with MARVEL Tōkon: Fighting Souls. Users report that these games crash on launch or during gameplay, with Windows sometimes rebooting entirely.
Embark Studios developer confirmed the issue in a message on Discord, noting that the crash is tied to a third-party kernel-level driver called inpoutx64.sys. This driver is not included with Windows and is typically installed by third-party software or hardware utilities, including Razer's software.
"We're aware of a new crash introduced with the release of a Windows update (KB5121003) that may be affecting some of you," the developer wrote. "The team is working on a fix, and we will keep you posted on any updates."
Embark narrowed the issue down to inpoutx64.sys, a driver that appears to have been modified or replaced by the Windows update, breaking compatibility with games that rely on direct port access for certain peripherals.
The Temporary Workaround
Embark Studios has provided a temporary workaround for affected users:
- Open Command Prompt as administrator
- Type
sc stop inpoutx64 - Type
sc delete inpoutx64 - Manually delete the inpoutx64.sys file from C:\Windows\System32\drivers
This removes the conflicting driver and allows the affected games to run without issue. Embark notes this is a temporary measure and a long-term fix is in development.
Other Reported Issues
Beyond game crashes, some users have reported Windows Hello PIN sign-in failures after installing KB5121003. One affected user described an "infinite loop" where Windows deletes and recreates the PIN key on every reboot, with the new key becoming corrupted before the next boot.
Windows Latest also observed performance issues including lower-than-usual frame rates and unexpected system reboots across multiple titles.
Should You Remove the Update?
Windows Latest recommends against removing KB5121003 unless the problems make your PC unusable. The update addresses more than 400 security vulnerabilities, and Microsoft has warned users against delaying security updates by more than three days.
The rise of AI-powered attacks makes system security more critical than ever. If your PC is functioning normally, the best course of action is to keep the update installed and wait for Microsoft to release a fix.
For more on Windows 11 issues, see the Windows Latest investigation. For a step-by-step troubleshooting guide, check the TechJournal fix page.