Windows 11’s recent update, KB5121003, released in August 2026, has emerged as a significant security enhancement, addressing over 400 vulnerabilities. However, it has also inadvertently disrupted the gaming experience for some users. Reports have surfaced from gamers experiencing crashes in titles such as ARC Raiders and The Finals following the installation of this mandatory update. The game studio, Embark, has acknowledged the issue, attributing the crashes to the new update.
In a message shared on Discord, Embark stated, “We’re aware of a new crash introduced with the release of a Windows update (KB5121003) that may be affecting some of you. The team is working on a fix, and we will keep you posted on any updates.” This update, which rolled out on August 11, advances PCs to Build 26200.9168 for those on version 25H2 and 26100.9168 for users on 24H2. For those uncertain about their current build, it can be found by navigating to Settings > System > About.
Windows 11 KB5121003 is crashing games on some PCs
Shortly after the rollout of the August 2026 Update, feedback from gamers, particularly those engaged with ARC Raiders, indicated that their gaming sessions were abruptly interrupted by crashes. Initially, there was speculation that recent driver updates from Nvidia or AMD might be to blame, as similar issues have arisen in the past. However, it appears that the compatibility of the update with a specific driver, inpoutx64.sys, has been compromised.
Users on platforms like Reddit reported that their games began crashing post-update, with some experiencing system reboots during gameplay. One player noted a staggering six crashes, some resulting in immediate restarts of their Windows environment. While previous reports indicated that the August 2026 Update could cause multiple reboots during installation due to Secure Boot certificate changes, these incidents differ as they occur during active gameplay.
Errors reported by users include “Hang detected on GameThread” and “EXCEPTIONACCESSVIOLATION,” all surfacing after the installation of Windows 11 KB5121003. Until recently, the exact cause of these crashes remained elusive, but Embark has shed light on the situation.
Windows 11 KB5121003 appears to have broken compatibility with inpoutx64.sys
Embark has identified that the update has affected the compatibility of the inpoutx64.sys driver, which is utilized by various hardware utilities and applications. In their Discord communication, they stated, “This is a crash related to the file inpoutx64.sys, which changed with the Windows update. We’re working towards a long-term fix, but in the meantime, there is a workaround solution that will safely remove the file in question and allow you to play the game without issue.”
For users experiencing these crashes, Embark has provided a workaround:
- Open the Start menu in Windows and type ‘cmd’ to find the Command Prompt.
- Right-click on the Command Prompt and select ‘Run as Administrator.’
- In the Command Prompt window, type ‘sc stop inpoutx64’ and press Enter.
- Then type ‘sc delete inpoutx64’ and press Enter. Close the window.
- Open File Explorer and navigate to C:WindowsSystem32drivers.
- Locate the file inpoutx64.sys and delete it.
This finding aligns with user reports, as one player discovered that the inpoutx64.sys file had been installed via a Razer Update Tool. Disabling the inpoutx64 service and restarting their PC resolved the crashes for them. However, Embark’s official workaround goes a step further by stopping, deleting the service, and removing the driver file entirely.
While the specifics of what changed in Windows 11 KB5121003 to disrupt compatibility with inpoutx64.sys remain unclear, further insights from Microsoft are anticipated. Additionally, several users have noted that uninstalling Windows 11 KB5121003 rectifies the issue, reinforcing the notion of a compatibility conflict between the update and the driver. Reports have also emerged of crashes in other games, including Marvel Tōkon: Fighting Souls, alongside early indications of display refresh rate drops, black screens, and other graphics-related anomalies following the cumulative update.
