Windows 11 KB5121003: Crashes, Black Screens and PIN Issues

Windows 11 KB5121003: Crashes, Black Screens and Sign-In Problems – Your Data Is Most Likely Still There

After installing the security update KB5121003 for Windows 11, affected users are reporting game crashes, unexpected restarts, black screens and Windows Hello PIN loops. Based on current knowledge, there is no evidence that personal files are being deleted – the data is usually intact, just temporarily inaccessible. What matters now is not to rush into resets or reinstallations.

What happened?

On 11 August 2026, Microsoft released the regular security and quality update KB5121003 for Windows 11 24H2 and 25H2. It brings systems up to OS builds 26100.9168 (Windows 11 24H2) and 26200.9168 (Windows 11 25H2) respectively, and is distributed automatically via Windows Update or Microsoft Update.

On 16 August 2026, the specialist outlet Windows Latest reported problems following installation: the games ARC Raiders and The Finals crash on some PCs, in some cases accompanied by an unexpected Windows restart. Developer Embark Studios confirmed the connection in a Discord message quoted by Windows Latest:

„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.“ – Embark Studios, quoted by Windows Latest

Technically, Embark traces the crashes back to an incompatibility with the file inpoutx64.sys – a third-party kernel driver, i.e. a system component that operates very close to the operating system kernel and enables direct hardware or port access:

„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.“ – Embark Studios, quoted by Windows Latest

In addition, the primary source documents isolated reports of black screens, faulty HDR, unexpectedly lower refresh rates as well as Windows Hello PIN loops, where the PIN has to be set up again after every restart. So far these symptoms are based on individual user reports and have not been confirmed by Microsoft as faults in KB5121003.

Microsoft itself lists no known issues on the official KB page for KB5121003 at the time of research (16 August 2026):

„Microsoft is not currently aware of any issues with this update.“ – Microsoft Support, KB5121003

As of 16 August 2026, there is no official fix, no known-issue entry, no recall and no withdrawal of the update.

Who and which devices are affected by the KB5121003 problems?

None of the sources reviewed gives a reliable figure for the number of affected users, devices or businesses. What is known so far is the following:

• Windows 11 24H2, OS build 26100.9168, after installing KB5121003
• Windows 11 25H2, OS build 26200.9168, after installing KB5121003
• Systems on which the third-party kernel driver or service inpoutx64.sys is present. Which manufacturer installed this driver and which driver versions are affected has not been published. The attribution to a Razer update tool mentioned in the primary source comes from a single user report and is not a confirmed manufacturer list.
• Affected applications according to the developer's confirmation: ARC Raiders and The Finals. Windows Latest also mentions reports concerning Marvel Tōkon: Fighting Souls and certain anti-cheat software – without official confirmation.

No specific hardware series, no particular notebook or PC models and no particular graphics cards have been confirmed as affected. So this is not a widespread outage, but a fault pattern that occurs with certain software and driver combinations.

Which symptoms point to the problem?

• A game or application crashes only since KB5121003 was installed, while everything ran stably before.
• Error messages such as „Hang detected on GameThread“ or EXCEPTION_ACCESS_VIOLATION.
• Isolated unexpected Windows restarts in connection with these crashes. These are to be distinguished from multiple restarts during the update installation, which according to Windows Latest can occur in the context of Secure Boot certificate deployment.
• Black screen after startup, reduced refresh rate, HDR misbehaviour or other display problems.
• Windows Hello demands a new PIN setup after every restart, or the existing Hello container is not loaded.

How to check whether you are affected – without risking your data

The following steps are purely diagnostic. They change nothing on the system and cannot endanger your files.

1. Check the update history: Start > Settings > Windows Update > Update history. Check whether "KB5121003" is listed as installed and note the installation date.
2. Check the build: Settings > System > About. The relevant OS builds are 26100.9168 (24H2) and 26200.9168 (25H2).
3. Put the timing in context: Did the crash, the black screen or the PIN problem only occur after the KB5121003 installation date? Then a connection is possible – but that does not prove it.
4. Document everything: Note the update ID, build number, the exact error message, the time, the affected application and any connected peripherals. This information is enormously helpful later on in distinguishing an update fault from a graphics driver or hardware problem.
5. With a black screen, first clarify the simple facts: Is there any signal reaching the monitor at all? Is a second screen or a dock connected? These observations are important clues – and they cost nothing.
6. For PIN problems: Use "Sign-in options" on the login screen to check whether another method already set up, such as the account password, works. If you get in, your profile is intact.

A note on the file inpoutx64.sys: its mere existence under C:\Windows\System32\drivers proves neither which software installed it nor that it is the cause in your case. Such a check belongs in experienced hands – all the more so on work computers.

What you should do now

The good news first: a data-deletion fault caused by KB5121003 is not documented in the sources researched. With a gaming, display or sign-in problem, there is no reason to assume your personal files have been deleted. They may, however, be temporarily inaccessible – because there is no picture, because sign-in fails, or because device encryption is asking for the BitLocker recovery key.

1. As long as you have access: back up immediately. Copy important files to an external drive or to cloud storage. Microsoft puts it unambiguously: "Always try to back up important files to an external drive or cloud service before proceeding with recovery options. Some options, like Reset or Reinstall, may result in data loss." If your backups have only been sporadic so far, you will find structure in the backup assistant.
2. No reinstallation, no reset as a first step. For a pure update, display or sign-in problem this is the wrong approach – and the most dangerous one.
3. No further installations on the affected drive. Every new piece of software, every additional tool writes data to the same storage medium.
4. Locate your BitLocker recovery key if your device is encrypted. Without it, many recovery routes are simply closed to you.
5. Do not blindly adopt the Embark workaround. The published interim solution relates specifically to inpoutx64.sys and is not a Microsoft solution. Because the driver may belong to third-party software or hardware utilities, removing it can impair other functions. On important work or company computers, professional support makes sense – and every intervention must be preceded by a backup.
6. Uninstalling KB5121003 is a judgement call, not a routine measure. Microsoft does document it as a recovery option ("If you've recently installed a Windows Update and the update is causing your device to have errors or other issues, uninstall the update to try to resolve the issue."), but explicitly warns that removing a security update also removes protection against known vulnerabilities. In any case, it is not a confirmed fix for KB5121003.

What you must not do under any circumstances

This section is the most important one. In practice, data is almost never lost after an update problem because of the update itself – but because of what is done afterwards with the best of intentions.

• "Reset this PC" with the "Remove everything" option – never as a reflex. This function deletes personal files, apps and settings. It is exactly what it sounds like. Microsoft explicitly advises backing up important files beforehand.
• No Windows reinstallation without a prior backup. According to Microsoft it typically removes files, apps and settings – and with a display, gaming or sign-in problem it is by far the most disproportionate step.
• No drive sanitisation, no Secure Erase, no destruction of encryption keys. Such data sanitisation procedures are – as the NIST SP 800-88 standard describes it – expressly designed to make access to data practically impossible. Anyone who runs them while actually trying to rescue files is working against themselves.
• Do not install data recovery or "repair" software on the same internal drive and do not write anything back to that drive while important files are still unsecured. Every new write operation can overwrite areas of data that you will need later.
• Do not repeatedly power off hard while a reset, a reinstallation or a recovery is running. Microsoft warns specifically that manually restarting during a reset can cause the entire process to fail – leaving a system that is afterwards neither old nor new.
• Do not delete kernel drivers on suspicion. Without knowing which software installed inpoutx64.sys, you risk knock-on problems with configuration and access – up to a system that no longer boots cleanly.
• Do not conclude from a black screen that the hard drive is defective and certainly do not open any device. There is no evidence of a physical storage defect in connection with KB5121003. If, however, clear hardware signs additionally appear – clicking noises, SMART errors, the drive is no longer detected at all – then the rule is: switch the device off and obtain a qualified diagnosis instead of continuing to boot.

It is precisely these well-meant rescue attempts that are, in our workshop, the most common reason why data ends up being genuinely unrecoverable. An update problem is fixable. A storage medium that has been reset, overwritten or reinstalled several times often is not.

Why this case belongs in professional hands – and how RESQ helps in practice

At first glance an update problem seems harmless: no water damage, no drop, no clicking drive. That is precisely where the danger lies. Because the device "merely" fails to start or to sign in, many affected users reach for the biggest tools Windows offers – reset, reinstall, clean up. Within a few minutes, that turns an access problem with intact data into genuine data loss.

Professional data recovery approaches this damage pattern differently. The key difference: work is never carried out on the original. Before anything is analysed or changed, a complete image copy of the storage medium is created. All further steps – checking the file system structure, reconstructing user profiles, dealing with an encrypted volume – take place on this copy. What is never touched on the original cannot be overwritten either. At home, exactly this safety layer is missing: there, every repair attempt inevitably starts on the very drive that ought to be left alone.

Then there is experience with precisely this fault pattern. A system that stays black after a security update or hangs in a sign-in loop has to be classified properly: is it a kernel-level driver incompatibility, a display problem, corrupted sign-in credentials – or is there coincidentally a hardware defect at the same time that merely looks like an update fault? This distinction determines whether rolling back the update is the right route or whether the data has to be brought to safety first. It cannot be made by trial and error, only by diagnosis – and trial and error is the most expensive approach of all when data is intact but inaccessible.

At RESQ, such a case follows clear steps:

1. Free initial assessment: You describe your case to us – build number, update ID, symptom, timing. We tell you how we assess the situation. Request your free initial assessment and a cost estimate here.
2. Diagnosis: We check whether this is purely an access or configuration problem or whether the storage medium itself is affected – and, where necessary, secure the data first.
3. An honest statement about the prospects and a cost estimate: Before any work begins, you find out what is possible, what cannot be promised with certainty, and what it would cost. Data recovery is always assessed case by case – we never give guarantees of success.
4. Your decision: Work only starts once you approve the cost estimate. If you would like to commission the case directly, you can create an order via your customer account.

You can read about our general approach, the damage patterns we handle and what the process looks like in detail on our page about data recovery at RESQ. If your case involves a classic hard drive in a notebook or desktop PC, you will find the relevant information under hard drive data recovery. If, on the other hand, the focus is not on data access but on a defective device, our repair service is the place to go.

The core message is simple: anyone who wants to be sure that their data is not lost through DIY attempts should have the case examined rather than trying to solve it themselves. With an update problem and intact data, the right moment for that is right now – before the first reset is started.

Can the data still be recovered after the KB5121003 problem?

Based on current knowledge, the answer is: the data is in all likelihood still present. There is no evidence of a deletion fault caused by KB5121003. What is missing, in most of the cases described, is access – due to a missing display, a failed sign-in or a BitLocker prompt. A controlled backup followed by patch or driver diagnostics can restore access.

Such cases only become unrecoverable through what happens afterwards: forced factory resets, reinstallations without a backup, deleted kernel drivers without a prior backup, sanitisation functions run on the wrong drive. Every one of these actions can turn a solvable problem into permanent data loss.

Conclusion

KB5121003 of 11 August 2026 brings Windows 11 up to builds 26100.9168 (24H2) and 26200.9168 (25H2). On some systems – particularly those where the third-party kernel driver inpoutx64.sys is present – ARC Raiders and The Finals have been crashing since then, in some cases with a system restart. There are isolated reports of black screens, HDR and refresh rate faults as well as Windows Hello PIN loops. As of 16 August 2026, Microsoft lists no known issues for this update; Embark Studios is working on a long-term solution and has published a driver-related interim measure. There is no reliable figure for the number of people affected.

For you as an affected user, this means: stay calm, back up instead of resetting, delete nothing on suspicion. If you currently cannot get to important files, do not keep experimenting – have the case examined. Request a free initial assessment of your case now and only decide afterwards, with a clear cost estimate and an honest assessment of the prospects.