Microsoft opens a KB5121003 known issue for the Windows 11 game crashes (August 20, 2026)

What changed on August 20

The crashes themselves are four days old. They were covered in the August 16 post as user reports tying KB5121003 to a third-party driver, with no Microsoft acknowledgement of any kind.

That gap closed. BleepingComputer, in a report published on August 20, 2026 at 02:51 AM EDT by Sergiu Gatlan, carries Microsoft's status wording: 'We are presently investigating to determine if this is an issue caused by Microsoft. We will provide an update when more information is available.' KB5121003 shipped on August 11, 2026 for Windows 11 25H2 and 24H2.

So the story moved from a pattern users had spotted to a defect on Microsoft's own board. Nothing about the crash changed on the affected PCs. What changed is that there is now an entry to track and a vendor position to hold Microsoft to.

Microsoft's own symptom list

The Microsoft Learn release health entry, opened on August 19, 2026 at 17:50 PT, sets out four symptoms in Microsoft's words: 'the game application becomes unresponsive', 'the game application closes without notice', 'the error EXCEPTION_ACCESS_VIOLATION is displayed', and 'the device restarts without warning'.

That last one is the reason this is worth more than a gaming footnote. A device restarting without warning is not a game problem, it is a data-loss problem, and it is now in Microsoft's own description rather than in a forum thread.

The entry limits affected platforms to Windows 11 25H2 and 24H2, with no server release listed. BleepingComputer lists the same symptom set, adding that the root cause has been attributed by Embark Studios to changes affecting the inpoutx64.sys kernel driver.

Embark Studios names the file

The most specific statement on August 20, 2026 does not come from Microsoft. Windows Latest on August 20, 2026 quotes Embark Studios, the developer of THE FINALS: 'This is a crash related to the file inpoutx64.sys, which changed with the Windows update.'

A studio pointing at a specific kernel file, by name, is a stronger claim than a pattern in crash reports. It is also the claim Microsoft has not endorsed: the release health entry says certain drivers are involved and the investigation is about whether Windows is at fault. Both positions can be true at once, and the difference between them is who ships the fix.

The games named are consistent across all three accounts: ARC Raiders, MARVEL Tokon: Fighting Souls and THE FINALS.

What acknowledgement does not change

There is no fix and no published date for one. There is no Microsoft workaround, which means the steps in circulation are still the studio's and the community's, and they involve deleting a kernel driver by hand.

There is also no answer yet on responsibility. Microsoft is investigating whether this is its own defect; the studio has already named a file that changed with the update. Until that is settled, nobody can say whether the remedy will arrive as a Windows update, as a driver update from the utility vendors, or as a block on the driver itself.

What acknowledgement does buy you is a place to look. An open entry gets updated, and that is where a fix or an official workaround will appear first.

What you can do today

Nothing has arrived to install, so the practical choice on August 20, 2026 is the driver removal or waiting. In order:

1. Check whether the driver is present at all. Open C:\Windows\System32\drivers and look for inpoutx64.sys. If it is absent, this known issue is not your crash.

2. If it is present and a named game crashes, open Command Prompt as administrator and run sc stop inpoutx64, then sc delete inpoutx64.

3. Delete C:\Windows\System32\drivers\inpoutx64.sys, restart, and launch the game again.

4. Weigh the cost first. The RGB lighting or hardware utility that installed the driver loses the capability that needed it, and reinstalling that utility may restore the driver.

5. Do not uninstall KB5121003 as a gaming fix. That gives up the August security fixes for a title you can wait on.

6. If your PC is restarting without warning rather than only dropping the game, save work before you launch anything, because that symptom is in Microsoft's own list.

7. Watch the release health entry for Windows 11 24H2 and 25H2. It is open, and an official workaround or fix will show up there before it shows up anywhere else.