Games crash with EXCEPTION_ACCESS_VIOLATION after Windows 11 KB5121003
Microsoft resolved this on 26 August 2026. The cause is not the Windows update itself but inpoutx64, a third-party kernel driver installed by RGB lighting, fan-control and sensor utilities. Windows now blocks that driver from loading on affected PCs, so on most home machines the fix arrives on its own — install updates, restart, and launch the game. If the block has not reached you, or your PC is managed by an IT department, disable the driver yourself using the steps below.
Start here
Microsoft opened this as a known issue on 19 August 2026 and closed it as Resolved on 26 August. Its investigation concluded that the Windows update did not cause the crashes: the trigger is a third-party driver that certain RGB and hardware-monitoring utilities install, and launching one of a handful of games is what sets it off. The first thing to establish is whether inpoutx64 is even on your machine — if it is not, this article is not your problem and none of the steps below will help.
Symptoms
- The game window stops responding a few seconds after launch
- The game closes with no error message at all
- An EXCEPTION_ACCESS_VIOLATION error appears
- The whole PC restarts without warning when you start a game
- It started after 11 August 2026, when KB5121003 installed
- Other games launch normally; only some titles are affected
- A Windows message appears saying a driver has been disabled, after which the game launches normally
Why this happens
inpoutx64 is a third-party kernel driver, and certain games trip over it
inpoutx64.sys is not part of Windows. It is an old third-party kernel-mode driver that gives a user-space program direct hardware port access, and it is bundled with a range of RGB lighting, fan-control, overclocking and sensor-monitoring utilities. Microsoft's investigation confirms the issue is not caused by Windows updates: it is related to peripherals or internal components with RGB lighting features that install drivers named similarly to inpoutx64, and launching certain games is what triggers it. Because the driver sits in kernel space alongside a game's anti-cheat driver, the fault takes the game — or the whole machine — down with it.
Check whether inpoutx64 is actually on your PC · Install the latest updates and restart — Windows now blocks the driver for you · Update or uninstall the utility that installed the driver · Disable the driver in the registry (Microsoft's workaround) · Delete the driver service and file (Embark Studios' workaround)
Only some games trip it
The titles named in reports are ARC Raiders, MARVEL Tokon: Fighting Souls and THE FINALS. Microsoft's automatic block currently targets devices that have the driver enabled and ARC Raiders installed, and Microsoft says it is working to expand the block to MARVEL Tokon: Fighting Souls; Embark Studios resolved the problem on its own side for THE FINALS. Games that never load a kernel-level anti-cheat driver are unlikely to be affected, which is why most of your library keeps working — and why the automatic block may not cover your particular title yet.
Check whether inpoutx64 is actually on your PC · Install the latest updates and restart — Windows now blocks the driver for you
Fixes
Check whether inpoutx64 is actually on your PC
about 2 minThis decides whether the rest of the article applies to you. Nothing here is worth doing if the driver is not installed.
Applies to: Windows 11 24H2, Windows 11 25H2
- Press the Windows key, type cmd, and open Command Prompt. You do not need administrator rights for this check.
sc query inpoutx64 - If the reply is "The specified service does not exist as an installed service", the driver is not there and this is a different problem. Read "When something else is wrong" below.
- If it returns a service with a STATE of RUNNING, this article applies. Confirm KB5121003 is installed too.
wmic qfe get HotFixID | findstr KB5121003
Confirmed by the vendor.
Install the latest updates and restart — Windows now blocks the driver for you
about 15 minMicrosoft's resolution is a block that stops inpoutx64 loading. It reaches unmanaged home and business PCs on its own, so on most machines there is nothing to edit.
Applies to: Windows 11 24H2, Windows 11 25H2, Devices not managed by an IT department
- Open Settings > Windows Update and select Check for updates. Install anything offered. Microsoft says the block is also included in the September 2026 security updates and later releases.
- Restart the PC. The block only takes effect after a restart.
- Launch the game. If the block has applied, Windows shows a message window telling you the driver has been disabled, and the game then launches as normal.
- If nothing has changed, give it time: Microsoft says the rollout can take up to 24 hours from 26 August 2026, 6 PM PT to reach all affected devices. If your PC is managed by an IT department, the block does not arrive automatically — use the registry step below instead.
Confirmed by the vendor.
Source: Microsoft, Microsoft, BleepingComputer
Update or uninstall the utility that installed the driver
about 10 minThe cleanest outcome is the vendor shipping a build that no longer needs this driver. Failing that, removing the app is fully reversible — you can reinstall it later.
Applies to: Windows 11 24H2, Windows 11 25H2
- Work out which app owns it. Candidates are your RGB lighting software, motherboard tuning and fan-control suites, and hardware sensor monitors. If several are installed, start with the one you installed most recently.
- Check that app for an update first. A vendor patch that drops inpoutx64 solves this without you losing anything.
- If there is no update, uninstall the app from Settings > Apps > Installed apps, then restart.
- Re-run the check from the previous fix. Some uninstallers leave the driver service behind, in which case you still need one of the steps below.
sc query inpoutx64
Source: Microsoft, Windows Latest
Disable the driver in the registry (Microsoft's workaround)
Advancedabout 5 minThis is the workaround Microsoft published, and it is still the route for PCs managed by an IT department or where the automatic block has not arrived. It stops the driver loading at boot without deleting anything, so it is straightforward to undo.
Applies to: Windows 11 24H2, Windows 11 25H2
Before you do this
This edits the registry. Back the registry up before you change anything — Microsoft's own guidance on this issue says the same. Microsoft states that its ongoing investigation does not indicate that disabling this key causes unintended behaviour, but the utility that installed the driver may lose whatever depended on it — RGB lighting, fan curves, macros or sensor readouts — until you set the value back.
First:
- Export a registry backup first: in Registry Editor, File > Export, All, and save the .reg file somewhere you can find it
- Press the Windows key, type regedit, and open Registry Editor.
- Paste this path into the address bar at the top and press Enter.
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\inpoutx64 - On the right, double-click the value named Start and set Value data to 4. That is the code for "disabled".
- Close Registry Editor and restart the PC, then launch the game.
- To undo it later, set Start back to the number it was before — 1 or 3 in most cases — or import the .reg backup you exported.
Confirmed by the vendor.
Source: Microsoft, BleepingComputer
Uninstall KB5121003
Advancedabout 15 minMicrosoft has concluded the update did not cause this, and the driver block ships in later updates, so rolling back now removes security fixes without addressing the trigger. Treat it as a last resort.
Applies to: Windows 11 24H2, Windows 11 25H2
Before you do this
KB5121003 is a security update. Removing it leaves your PC without the August 2026 security fixes until you reinstall it, and Windows Update will try to reinstall it on its own. Prefer disabling the driver over rolling back the update.
- Open Settings > Windows Update > Update history.
- Scroll to the bottom and select Uninstall updates.
- Find KB5121003 in the list and select Uninstall, then restart.
- Pause updates for a week or two so it does not reinstall immediately: Settings > Windows Update > Pause updates. Unpause once a fixed driver or a Microsoft fix is available.
Source: Microsoft, Windows Latest
Delete the driver service and file (Embark Studios' workaround)
Can cause data lossabout 10 minThis is what ARC Raiders' developer told players to do. It removes the driver outright rather than disabling it, so use it only if the registry route did not stick.
Applies to: Windows 11 24H2, Windows 11 25H2
Before you do this
This deletes a driver file. If the utility that installed it does not put it back, you will lose whatever that utility used it for — RGB control, fan curves, macros, sensor monitoring — until you reinstall the application. Do not delete any file other than the one named here.
First:
- Create a System Restore point: press the Windows key, type "Create a restore point", open it, select your system drive and choose Create
- Know which application installed the driver, so you can reinstall it if you need those features back
- Press the Windows key, type cmd, right-click Command Prompt and choose Run as administrator.
- Stop the driver service.
sc stop inpoutx64 - Delete the service registration.
sc delete inpoutx64 - Open C:\Windows\System32\drivers, find inpoutx64.sys, and delete it. Delete nothing else in that folder.
- Restart the PC and launch the game.
Source: Windows Latest
Known issues
Microsoft's known issue "Some games become unresponsive when certain drivers are present" was opened on 19 August 2026 and marked Resolved on 26 August 2026. Microsoft says the issue is not caused by Windows updates; it resolved it with a block that prevents the inpoutx64 driver from loading, which propagates automatically to devices not managed by an IT department and is included in the September 2026 security updates.
Affects Windows 11 25H2 (OS Build 26200.9168), Windows 11 24H2 (OS Build 26100.9168) · Status: fixed
If none of this worked
If `sc query inpoutx64` says the service does not exist, stop here — this is not your crash. The same symptoms have plenty of other causes: an unstable memory overclock or XMP/EXPO profile, an overheating or power-starved GPU, a corrupted shader cache, or a game update that shipped its own bug. Note too that Microsoft's block currently targets a specific set of games, so if your title is not among them the block will not have been applied to your PC even though the driver is present. If it only happens in one game and started with a game patch rather than a Windows one, the developer's own support channel is the faster route. And if the crash is gone but your RAM or motherboard lighting, fan curves or sensors stopped along with it, that is the expected cost of blocking this driver — see the companion article on getting them back.
Common questions
- Is inpoutx64.sys malware?
- No. It is a legitimate, very old third-party driver that gives software direct access to hardware I/O ports. Plenty of RGB lighting, fan-control, overclocking and sensor-monitoring tools bundle it. It is not a Windows component, which is why removing it does not damage the operating system — it only affects whichever application relies on it.
- Which app installed it on my PC?
- Windows does not record that, and the driver ships inside so many utilities that there is no reliable lookup. Work backwards from what you have installed: motherboard tuning suites, RGB lighting controllers, fan-curve tools and hardware monitors are the usual candidates. If uninstalling one does not remove the driver service, uninstall it and then use the registry or deletion step.
- Windows told me a driver was disabled when I launched the game. Is that bad?
- No — that is Microsoft's fix working. The resolution Microsoft shipped on 26 August 2026 blocks inpoutx64 from loading and shows a message window saying so; the game then launches as normal. The trade-off is that whatever the driver was doing for your RGB or fan-control utility stops working. Some tools have already moved off it: OpenRGB's documentation says it now uses the PawnIO driver for SMBus access, and Fan Control ships a PawnIO build from V238. Updating the utility is what brings those devices back.
- Should I just uninstall the Windows update?
- No. Microsoft's investigation concluded that the update did not cause this, and the driver block ships in the September 2026 security updates and later — so rolling back removes security fixes and takes you further from the fix. Disabling the inpoutx64 driver targets the actual trigger.
- My game is not on Microsoft's list. Could this still be it?
- Possibly. Microsoft names ARC Raiders, MARVEL Tokon: Fighting Souls and THE FINALS because those are the titles in the reports it received, not because it has established the full set. If your crashes started on 11 August 2026, the driver is present, and disabling it stops the crashes, the cause is the same regardless of the title.
- Has Microsoft fixed this?
- Yes. Microsoft marked the known issue Resolved on 26 August 2026. The fix is a block that stops the inpoutx64 driver loading, aimed at devices that have the driver enabled and ARC Raiders installed; Microsoft says it is working to expand the block to MARVEL Tokon: Fighting Souls, and Embark Studios resolved it separately for THE FINALS. Enterprise-managed devices do not get the block automatically and need the registry workaround. A vendor update to your RGB utility that drops the driver would also resolve it.
Did this fix work?
If a step is wrong, outdated, or did not help, telling us is the fastest way to get it corrected. Reports are reviewed before new articles.
Report a problem with this pageRelated problems
- Game Crashes When You Alt-Tab on Windows 11
- Game Shows a Black Screen on Launch but the Audio Plays
- Windows Update Stuck Downloading or Failing to Install
- RGB Lighting and Fan Control Stopped Working After inpoutx64 Was Blocked
- Call of Duty "Failed Attestation Status" when TPM 2.0 and Secure Boot are already on
- Do new NVIDIA GeForce drivers still support Windows 10?
Sources
Microsoft · Release notes · checked Sep 30, 2026
- Microsoft opened the known issue on 2026-08-19 and marked it Resolved on 2026-08-26 at 23:30 PT
- Microsoft states that its investigation confirms this issue is not caused by Windows updates, and that it is related to peripherals or internal components with RGB lighting features
- Such devices may install drivers or code components with file names similar to inpoutx64, and the issue is then triggered by launching certain games
- Symptoms Microsoft lists are the game becoming unresponsive, closing without notice, EXCEPTION_ACCESS_VIOLATION, and the device restarting without warning
- ARC Raiders, MARVEL Tokon: Fighting Souls and THE FINALS are the titles named in reports
- The resolution is a block that prevents the inpoutx64 driver from loading; it disables the driver and displays a message window, after which the game launches as normal
- The block targets devices with the driver enabled and ARC Raiders installed, and Microsoft is working to expand it to MARVEL Tokon: Fighting Souls
- Embark Studios resolved the issue for devices running THE FINALS
- The resolution propagates automatically to consumer and business devices not managed by IT departments, requires a device restart, and may take up to 24 hours from 2026-08-26 18:00 PT
- The driver block will also be included in the September 2026 Windows security updates and subsequent releases
- Enterprise-managed devices do not receive the resolution automatically; IT administrators must apply the workaround
- Microsoft's workaround is setting HKLM\SYSTEM\CurrentControlSet\Services\inpoutx64\Start to 4 and restarting
- Microsoft says ongoing investigation does not indicate that disabling this registry key can result in unintended behaviour, and that the change can be undone by restoring the previous value
- Affected platforms are Windows 11 version 25H2 and version 24H2
- As of 30 September 2026 this entry lives on the resolved-issues page; it has aged off the 25H2 known-issues page, which shows open issues and content updated in the last 30 days.
Microsoft · Support page · checked Sep 30, 2026
- KB5121003 was released on 11 August 2026 as OS Builds 26100.9168 and 26200.9168
- The KB page lists the games-becoming-unresponsive known issue as resolved as of 27 August 2026
- The resolution is available automatically to consumer and business devices that are not managed by IT departments, while enterprise-managed devices require administrator action
OpenRGB · Documentation · checked Sep 30, 2026
- On Windows, OpenRGB uses the PawnIO driver to access the SMBus interface; early versions used WinRing0 and even earlier versions used InpOut32.
- OpenRGB's documentation says those older drivers are no longer used and should be removed to avoid warnings by anti-cheat and anti-virus software.
BleepingComputer · News · checked Sep 30, 2026
- Reported on 27 August 2026 that Microsoft began rolling out the block that stops the inpoutx64 driver loading
- Quotes Microsoft saying that ongoing investigation does not indicate that disabling this registry key can result in unintended behaviour
Windows Latest · News · checked Sep 30, 2026
- An Embark Studios developer posted on Discord that the studio is aware of a new crash affecting players after KB5121003
- Embark's workaround is sc stop inpoutx64, sc delete inpoutx64, then deleting inpoutx64.sys from C:\Windows\System32\drivers
- inpoutx64.sys is a third-party kernel-mode port I/O driver that ships with hardware and lighting utilities, not a Windows component
- Removing the driver can disable RGB, fan control, macro and sensor features in the utility that installed it