Fix Game Crashes and Unexpected PC Restarts on Windows 11.

If a game started crashing, freezing, displaying EXCEPTION_ACCESS_VIOLATION, or causing your PC to restart unexpectedly after installing Windows 11 KB5121003, your computer may be affected by a known compatibility issue involving the inpoutx64 driver.

Microsoft initially investigated the problem after reports appeared following KB5121003 and later Windows updates. However, Microsoft has now confirmed that Windows Update itself is not the cause. The problem is associated with certain RGB-capable peripherals or internal components that install drivers or software components with names similar to inpoutx64.

Microsoft has started blocking the problematic driver automatically on targeted affected computers. If the problem continues, you can check whether inpoutx64 is installed and use Microsoft's Registry workaround to prevent the driver from loading.

How to Fix Game Crashes or Other Gaming Issues on Windows 11 After Installing KB5121003.*

IMPORTANT: KB5121003 is a Windows security update. Do not uninstall it as your first troubleshooting step. Microsoft now provides a more targeted workaround for the actual compatibility problem.

Step 1. Check Whether Your PC Is Affected

This issue applies to Windows 11 versions 24H2 and 25H2. Games identified in reports include:

• ARC Raiders
• MARVEL Tōkon: Fighting Souls
• THE FINALS

Microsoft says an affected game may:

• Stop responding.
• Close unexpectedly.
• Display EXCEPTION_ACCESS_VIOLATION.
• Cause Windows to restart without warning.

The list of games is not necessarily complete, and Microsoft has not published a list of specific RGB devices or manufacturers affected by the problem.

If the problem started after the August 11, 2026 security update, you can also check whether KB5121003 is installed. To do that:

1. Open Settings > Windows Update > Update history.
2. Under Quality Updates, look for KB5121003.

Step 2. Check Whether inpoutx64.sys driver Is Installed

The next step is to determine whether the inpoutx64 driver associated with the compatibility problem exists on your computer.

1. Right-click Start and select Terminal (Admin) or Windows PowerShell (Admin).

2. Type the following command and press Enter:

• Test-Path "C:\Windows\System32\drivers\inpoutx64.sys"

If PowerShell returns "True", the inpoutx64.sys file exists on the computer.

3. Since finding the file does not by itself prove that inpoutx64 is causing your game to crash, also check if the corresponding driver service is present by typing:

• sc.exe query inpoutx64

4. Based on the results, do the following:

• If the inpoutx64 driver and its service are present, proceed to the next step and disable the driver if the corresponding Registry key exists. Then, restart Windows and check whether the problem is resolved.
• If neither the inpoutx64 driver nor its service is present, as shown in the screenshot below, your gaming problem may have a different cause.

Step 3. Fix the Problem by Disabling inpoutx64

After finding that inpoutx64 driver and its service are present, apply Microsoft's official workaround is to prevent the inpoutx64 driver/service from loading by changing its Start Registry value to 4.

WARNING: Incorrect Registry changes can cause Windows or installed software to stop working correctly. Before making the change, record the existing Start value or back up the inpoutx64 registry key so you can restore it if necessary.

To disable the inpoutx64.sys driver:

1. Press Windows + R to open the Run command box.

2. Type: regedit and click OK.

3. Navigate to:

• HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\inpoutx64

* Note: If the inpoutx64 key does not exist, do not create it.

WARNING: Before changing anything, note the current value of Start REG_DWORD value, or right-click the inpoutx64 key and select Export to save a backup. (You will need this value if you later decide to restore the driver).

4. At the right-pane, double-click the Start value.

5. Change Value data to: 4 and click OK

6. Close Registry Editor and restart the computer.

7. After restarting, launch the game that previously crashed and check whether it now runs normally.

Notes:

1. Disabling inpoutx64 may affect RGB functionality or software that depends on the driver. Microsoft states that its ongoing investigation has not indicated unintended behavior from the change, but keeping the original Registry value allows you to restore the previous configuration if necessary.

2. Microsoft is also deploying an automatic compatibility block that prevents inpoutx64 from loading on targeted affected PCs. The initial deployment targets systems with inpoutx64 enabled and ARC Raiders installed, with coverage being expanded to MARVEL Tōkon: Fighting Souls. Microsoft states that THE FINALS has been addressed separately by Embark Studios.

How to Verify That the Problem Is Fixed

After restarting the computer:

1. Launch the game that previously failed.
2. Repeat the action that normally caused the game to freeze, close, or restart the computer.
3. Confirm that the game no longer crashes or displays EXCEPTION_ACCESS_VIOLATION.
4. Verify that Windows no longer restarts unexpectedly while running the affected game.

Also check your RGB hardware or control software to make sure any functionality you need still works after disabling the driver.

If the game now works normally, the symptoms were consistent with Microsoft's documented inpoutx64 compatibility issue.

Should You Uninstall KB5121003?

No, not as the primary solution.

Some users reported that uninstalling KB5121003 temporarily stopped their crashes. However, Microsoft has confirmed that the problem is associated with certain RGB-capable peripherals or internal components that install drivers or software components with file names similar to inpoutx64.

More importantly, KB5121003 is the August 2026 Windows security update. Removing it also removes the security fixes included with that cumulative update.

Microsoft's current solution targets the problematic driver instead, so disabling inpoutx64 is preferable to uninstalling the security update when your PC matches the documented issue.

You should also avoid deleting inpoutx64.sys or its driver service. Earlier community workarounds recommended removing them, but Microsoft's Registry method is less invasive and reversible.

What to Do If the Game Still Crashes

If inpoutx64 is not installed, or the game continues to crash after disabling it and restarting Windows, don't assume KB5121003 is responsible.

Microsoft has not stated that every game crash or unexpected Windows restart after the August update belongs to this issue.

In that situation, restore the original Registry value if the workaround made no difference and continue troubleshooting the game or computer for another cause.

The same applies if you see Kernel-Power Event ID 41 after an unexpected restart. Event ID 41 confirms that Windows did not shut down normally, but it does not identify inpoutx64 as the cause.

Conclusion

If your games started crashing or your Windows 11 PC began restarting unexpectedly after KB5121003, first check whether the symptoms match Microsoft's documented inpoutx64 compatibility issue.

Microsoft has linked the crashes to an interaction involving certain RGB-related components and drivers such as inpoutx64. Microsoft has not published a complete technical explanation of the interaction between the RGB-related components and the affected games.

If inpoutx64 is present, use Microsoft's Registry workaround to disable the driver, restart Windows, and test the affected game again. Avoid uninstalling KB5121003 or deleting the driver when the supported, reversible workaround resolves the problem.

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Konstantinos Tsoukalas

Konstantinos is the founder and administrator of Wintips.org. Since 1995 he works and provides IT support as a computer and network expert to individuals and large companies. He is specialized in solving problems related to Windows or other Microsoft products (Windows Server, Office, Microsoft 365, etc.).

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