A driver block ends the KB5121003 game crashes on Windows 11 (August 26, 2026)
Chapters
What changed on August 26
The crashes started with the August update. Windows Latest tied them to inpoutx64.sys on August 16, 2026, a third-party kernel-level port-access driver shipped by RGB lighting and hardware utilities, and I covered those first reports in the August 16 post. The games named in Microsoft's own known issues for KB5121003 are ARC Raiders, MARVEL Tokon: Fighting Souls and THE FINALS (Microsoft Support, August 11, 2026), on OS builds 26200.9168 for 25H2 and 26100.9168 for 24H2.
What is new today is the resolution. Microsoft's release health entry for the issue now reads resolved, and the mechanism is a driver block rather than a patch.
TL;DR
Microsoft has closed the Windows 11 game-crash issue that followed the August security update KB5121003, and its own release health entry records the resolution at 23:30 PT on August 26, 2026. The resolution is not a change to Windows: it is a block that prevents the third-party inpoutx64 driver from loading. Propagation starts at 6 PM PT on August 26, 2026, Microsoft says it might take up to 24 hours to reach all affected devices, a restart is required, and enterprise-managed devices do not receive it automatically.
- Microsoft's wording: "This issue is resolved by a block that prevents the inpoutx64 driver from loading."
- The issue was opened on 2026-08-19 at 17:50 PT and marked resolved on 2026-08-26 at 23:30 PT.
- The block first targets devices that have the driver enabled and ARC Raiders installed, and Microsoft says it is working to expand it to MARVEL Tokon: Fighting Souls. THE FINALS was addressed by Embark Studios rather than by the block.
- Once the driver is blocked, a message window explains the disablement and the game launches as normal.
- Enterprise-managed devices get nothing automatically: an administrator sets the inpoutx64 service Start value to 4 and restarts.
What the block does
The block stops inpoutx64 from loading. Microsoft's conclusion is that the fault was not in the Windows update but in RGB-lighting peripherals and internal components that install drivers with names similar to inpoutx64. With the block in place the driver is disabled, a message window explains the disablement, and the game then launches as normal.
It is worth being clear about what that means. A resolution that does not change Windows also does not restore the driver. Whatever the RGB or fan-control utility used direct port access for stops working. The game runs, the lighting control may not, and that is the trade Microsoft has chosen on your behalf.
The block is also not uniform across the three games. Microsoft says it initially targets devices that have the driver enabled and ARC Raiders installed, and that it is working to expand it to MARVEL Tokon: Fighting Souls. THE FINALS was addressed by Embark Studios rather than by the block, so that one was never waiting on Microsoft.
Timing and reach
There is no package to install, which is why the entry gives a propagation window instead of a build number. The dates on the record:
| Item | Value |
|---|---|
| Issue opened | 2026-08-19, 17:50 PT |
| Issue resolved | 2026-08-26, 23:30 PT |
| Propagation starts | August 26, 2026, 6 PM PT |
| Time to reach all affected devices | up to 24 hours |
| Device restart | required |
| Enterprise-managed devices | not covered automatically |
Where the block does not go
Enterprise-managed devices are excluded from the automatic propagation. On those machines the crashes continue until an administrator disables the driver by hand: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\inpoutx64, set the Start value to 4, then restart.
Microsoft says applying that alongside the block is safe, and that the change is reversible by restoring the previous value. The cost is the same as the block's, plus the operational cost of pushing a registry change and a reboot across a fleet. Note the old Start value before you change it, because that number is your undo.
What you can do today
If a PC has been crashing in these games since the August update, this is the order as of August 26, 2026.
1. Restart the PC. The block needs a restart, and propagation began at 6 PM PT on August 26, 2026 with up to 24 hours to reach every affected device.
2. Launch the game. If the block has arrived you get a message window saying inpoutx64 was disabled, and the game starts.
3. If the crashes continue and an IT department manages the machine, stop waiting. The resolution does not propagate to managed devices at all.
4. On a managed device, note the current Start value at HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\inpoutx64, set Start to 4 and restart.
5. Expect the RGB or fan-control utility that installed the driver to lose the function that needed it. If that function matters more than the game, the honest answer is to wait for that vendor rather than to remove the August security update.
6. Keep KB5121003 installed either way. It is the month's security update, and the crash issue now has a resolution that does not ask you to give it up.
If the registry work across a stack of machines is not something you want to do by hand, Get XLAnt.
Frequently asked questions
Do I need to install anything to get this resolution?
No. Microsoft resolved the issue with a block that prevents the inpoutx64 driver from loading, and the block propagates on its own to devices that are not managed by IT. A restart is required. Propagation began at 6 PM PT on August 26, 2026 and Microsoft said it might take up to 24 hours to reach all affected devices.
Will my RGB software still work?
The function that needed direct port access through inpoutx64 will not. The driver is blocked from loading, and Microsoft's own framing is that peripherals and components installing drivers of that kind are the source of the crashes. Anything else the utility does is unaffected by the block.