Microsoft is investigating a Windows 11 issue in the August 2026 security update KB5121003 that can make certain games freeze, close unexpectedly, show EXCEPTION_ACCESS_VIOLATION errors, or restart the PC. The confirmed reports affect Windows 11 versions 24H2 and 25H2, and Microsoft says its investigation currently points to some RGB-lighting peripherals or internal components that install drivers with names similar to inpoutx64.
The important part for gamers is that this is a confirmed known issue, but it is not a reason for every Windows 11 user to remove the August security update. Microsoft is still investigating, and most PCs are not reported as affected. Here is what is known, what is still uncertain, and the safest way to troubleshoot without turning an isolated game crash into a larger Windows problem.
What is happening with Windows 11 KB5121003?
KB5121003 is Microsoft’s August 11, 2026 security update for Windows 11 24H2 and 25H2. It moves those releases to OS builds 26100.9168 and 26200.9168 respectively. On August 20, Microsoft added reports of certain games becoming unresponsive to the update’s official known-issues section.
Microsoft lists four symptoms on affected systems:
- a game becomes unresponsive;
- a game closes without notice;
- Windows displays an
EXCEPTION_ACCESS_VIOLATIONerror; or - the device restarts without warning.
The company specifically names ARC Raiders, MARVEL Tōkon: Fighting Souls, and THE FINALS among games identified in reports. That does not mean every player of those games will experience the problem.
Which Windows versions are affected?
| Windows release | August update | Build | Known gaming issue |
|---|---|---|---|
| Windows 11 25H2 | KB5121003 | 26200.9168 | Microsoft investigating |
| Windows 11 24H2 | KB5121003 | 26100.9168 | Microsoft investigating |
| Windows 11 26H1 | KB5121000 | 28000.2704 | Not listed in Microsoft’s current KB5121000 known issues |
You can check your version under Settings > System > About. If you are troubleshooting a new gaming problem, also open Settings > Windows Update > Update history and confirm whether KB5121003 is installed before assuming the update is responsible.
Why are RGB devices part of the investigation?
Microsoft says its ongoing investigation indicates an association with certain peripherals or internal components that support RGB lighting. Those devices can install drivers or software components with file names similar to inpoutx64. On systems where these drivers are present, launching certain games can trigger the problem.
This detail matters because it narrows the issue. The current evidence does not show that KB5121003 breaks gaming on every Windows 11 PC. A machine with RGB control software, hardware-monitoring utilities, or related low-level components may have a different risk profile from a clean Windows installation.
Embark Studios, the developer behind ARC Raiders and THE FINALS, separately identified inpoutx64.sys while investigating crashes. Microsoft, however, has not yet published a final root-cause determination or permanent fix.
Should you uninstall KB5121003?
Do not uninstall the update preemptively if your games are working normally. KB5121003 is a security update, so removing it also removes the protections delivered with that cumulative update. For an unaffected PC, there is little benefit in rolling it back merely because a known issue exists.
If you are affected, start with lower-risk checks: update the game, update or temporarily disable the relevant RGB/control utility if its vendor recommends doing so, restart Windows, and check Microsoft’s KB5121003 page for a newer status. Microsoft is asking affected users to submit reports through Feedback Hub by pressing Windows key + F.
Some third-party reports describe uninstalling KB5121003 or manually removing the implicated driver as temporary workarounds. Those steps can carry security or hardware-control trade-offs, so BrandLigo does not recommend deleting a kernel driver solely from an unofficial recipe. If you use a workaround, follow guidance from Microsoft or the hardware/game vendor responsible for the component and understand what functionality you are disabling.
What to do if ARC Raiders, THE FINALS, or MARVEL Tōkon crashes
- Confirm the update. Verify that KB5121003 appears in Windows Update history.
- Check the symptom. Note whether the game freezes, exits, produces EXCEPTION_ACCESS_VIOLATION, or restarts the computer.
- Identify RGB and hardware-control software. Check utilities installed for lighting, fan control, motherboard tools, or peripherals. Do not delete drivers blindly.
- Update the game and device software. A vendor-side compatibility update may resolve the interaction without removing Windows security fixes.
- Check Microsoft’s known-issue page. The KB article is the authoritative source for changes to the investigation and any official resolution.
- Send a Feedback Hub report. Microsoft specifically requests reports from affected users.
- Use rollback only as a considered fallback. If the PC is unusable for the workload and no supported vendor fix exists, evaluate rollback against the security cost and reinstall the corrected update when Microsoft resolves the issue.
Is this related to the 2026 Secure Boot certificate change?
KB5121003 also includes additional targeting data for Microsoft’s rollout of new Secure Boot certificates, but Microsoft has not said that the Secure Boot certificate transition causes the game crashes. These are separate items on the same cumulative update.
BrandLigo has a dedicated Windows Secure Boot certificate expiration guide explaining why certificates began expiring in June 2026 and what Microsoft is doing about it. Keeping the two issues separate avoids a common troubleshooting mistake: assuming everything delivered in the same Windows update has the same root cause.
What else changed in the August 2026 Windows update?
Microsoft’s release notes say KB5121003 includes security improvements, continued Secure Boot certificate deployment, servicing-stack updates, and updates to AI components that apply to Copilot+ PCs. If you are evaluating whether newer AI-capable hardware matters for your next machine, see BrandLigo’s AI PC and NPU guide.
The August update also sits close to an important lifecycle date: Windows 11 24H2 Home and Pro reach end of updates on October 13, 2026. Microsoft recommends moving to a supported Windows 11 version to continue receiving security and quality updates.
How this changes the advice for Windows gamers
The best response is targeted troubleshooting, not a blanket rollback. First establish that the affected PC is on 24H2 or 25H2 with KB5121003, then look for the specific game symptoms and relevant RGB or low-level device software. If those conditions do not match, investigate ordinary GPU drivers, game files, thermals, overlays, anti-cheat software, and hardware stability instead of forcing this known issue to fit.
For people shopping for a newer Windows machine, this bug is also a reminder that compatibility depends on the whole system—not only the CPU and GPU. Firmware, peripheral utilities, kernel drivers, and Windows servicing can all interact. BrandLigo’s 2026 AI PC guide covers the newer hardware side, while the HP company profile provides verified context on one major Windows PC vendor and its current PC portfolio.
Frequently asked questions
Does KB5121003 break all Windows 11 games?
No. Microsoft describes reports involving certain games on affected systems. The investigation points toward an interaction with some RGB-related peripherals or internal components and associated drivers, not a universal Windows gaming failure.
Which games has Microsoft named?
Microsoft’s current KB5121003 page names ARC Raiders, MARVEL Tōkon: Fighting Souls, and THE FINALS among reported affected games.
What is inpoutx64.sys?
It is a low-level driver associated with hardware access and can be installed by certain device or utility software. Microsoft says affected systems may contain drivers or components with file names similar to inpoutx64. Do not remove a kernel driver unless you understand which software or hardware depends on it and have trusted vendor guidance.
Should I pause Windows Update?
If your PC is unaffected, Microsoft has not advised all users to pause updates because of this issue. Security updates contain important protections. Affected users should follow the evolving Microsoft and vendor guidance rather than applying a blanket pause.
Is Windows 11 26H1 affected?
Microsoft’s current known-issue entry is on KB5121003 for Windows 11 24H2 and 25H2. The August 26H1 update is KB5121000, and Microsoft’s current page does not list this gaming issue.
When will Microsoft fix the crashes?
Microsoft says it is investigating and will provide additional details as they become available. As of August 22, 2026, the KB5121003 support page does not list a permanent Microsoft resolution.
About this article. BrandLigo checked the current Microsoft support documentation and independent reporting on August 22, 2026. Because the investigation is active, details may change as Microsoft or affected vendors publish fixes.
Sources: Microsoft Support: KB5121003; Microsoft Support: KB5121000; BleepingComputer; PC Gamer.