August 2026 Windows Update — Known Problems and Fixes

August's Windows update has been out over two weeks now. Eight problems have surfaced so far. Here's what they are and what you should do about each one.

Fake "Turn on Virus Protection" warning

After installing KB5121003, some Windows 11 PCs are showing a persistent "Turn on Virus Protection" notification in Windows Security. Looks alarming. Your antivirus is fine.

The alert appears about four minutes after you log in, at the same uptime mark every time. Consistent enough that people spotted it wasn't random. Microsoft support has confirmed this is not a real problem: Windows Defender is fully active. The notification is wrong. It's a display bug in Windows Security, not a genuine warning about your protection.

Reports have come in from Windows 11 users on Microsoft Community Hub and the ElevenForum KB5121003 thread. Different manufacturers, different hardware configurations, all seeing the same notification at the same moment after login. That consistency is what told Microsoft this is a bug. There's still no official patch. They're collecting reports to formally confirm it before one goes out. Update, 15 August: two workarounds have turned up since I first wrote this, and the steps for both are further down the page.

In the meantime, you have two options.

First: ignore it. Your PC is protected. Defender is running; the display is simply wrong.

Second: check for yourself. If you'd rather see that everything's fine with your own eyes, you can do that in about a minute.

How to confirm your antivirus is working

1. Press the Windows key on your keyboard. It's the key with the four-part flag symbol, usually at the bottom-left next to the space bar.
2. A search bar appears. Type Windows Security and press Enter.
3. The Windows Security app opens. In the left-hand menu, click Virus & threat protection. If there's no visible menu, click the three horizontal lines at the top-left of the app first to open it.
4. Look at the top of the page. You should see a green tick and the words No action needed.

If you see that, Defender is working normally. The notification you got is a bug. Dismiss it and carry on.

How to stop the notification appearing

Neither of these came from Microsoft, so treat them as workarounds rather than a proper patch. The first one is the one to try. It goes after the bug itself and takes about two minutes.

Option A: repair the Windows Security app. This works on every version of Windows 11, Home included. Nothing in these steps switches off your protection or removes Defender.

1. Hold down the Windows key (the one with the four-part flag symbol, bottom-left near the space bar) and press the letter I. The Settings window opens.
2. In the list down the left-hand side, click Apps.
3. Click Installed apps.
4. Scroll down the list of programs until you find Windows Security. Over on the right of that row there are three dots stacked in a line. Click them.
5. Click Advanced options.
6. Scroll down that page until you see a button marked Repair. Click it and leave it alone until it's finished.
7. Restart your PC. Log back in, give it five minutes or so, and see whether the notification turns up again.

Still there? Go back to that same Advanced options page and click Reset instead, which sits just below Repair. Reset wipes the app's saved display settings and starts it fresh. It doesn't turn Defender off and it doesn't uninstall anything. Repair first, though. It's the gentler of the two and it usually does the job on its own.

Option B: hide the notification. Windows 11 Pro and Enterprise only. If your PC came with Windows 11 Home, which most home machines do, this screen doesn't exist and step 2 will just give you an error. Skip to the end.

1. Hold down the Windows key and press the letter R. A small box appears near the bottom-left of the screen.
2. Type gpedit.msc and press Enter. A window called Local Group Policy Editor opens.
3. In the panel on the left, double-click Computer Configuration, then Administrative Templates, then Windows Components, then Windows Security, then Notifications.
4. In the panel on the right, double-click Hide all notifications.
5. Click the circle next to Enabled, click OK, and close the window.
6. Restart your PC.

Worth being clear about what Option B actually does. It mutes Windows Security. The bug is still sat there underneath, and you won't get told about a real problem either, because you've silenced every message the app sends. That's a reasonable trade if the false alert is driving you round the bend. It's not something I'd leave switched on once the patch lands.

Games crashing after the update

This one turned up on 16 August and it's a proper fault, not a display glitch. KB5121003 tightened up kernel-level security in Windows, and that change broke a driver called inpoutx64.sys. It's an old, low-level driver that lets software talk directly to hardware. Some anti-cheat systems load it, and so do a fair few RGB lighting and fan control utilities. Since the update went on, anything that loads it can bring the game or the program down with it.

What you actually see varies. Crash straight to desktop. A "Hang detected on GameThread" message. An EXCEPTION_ACCESS_VIOLATION error. A few people have had the screen go black, and a smaller number have had the whole PC restart itself mid-game.

ARC Raiders and THE FINALS are the confirmed ones so far. Embark Studios, who make ARC Raiders, have publicly said the August update is the cause, which is quicker and straighter than most studios manage. Both games run Denuvo Anti-Cheat, so if you play anything else with Denuvo on it, keep an eye out. Away from gaming, any program that reaches hardware through that same driver could misbehave, and in practice that means the RGB lighting software that came with your keyboard, mouse or case fans.

If you don't game and you've never installed any of that lighting software, this one isn't yours to worry about. Carry on.

What you can do about it

Quite a lot now, which wasn't the case when I first wrote this section. Microsoft has put out an automatic fix, and there's a manual workaround if that hasn't reached your machine yet. The updates below run in date order, so read to the bottom before you start typing anything into a Command Prompt.

Update (17 August 2026): Embark Studios (the team behind ARC Raiders) have confirmed a workaround. You don't need to uninstall the security update — just remove the driver that's causing the conflict:

1. Click the Start menu (the Windows logo at the bottom of your screen) and type cmd.
2. Right-click Command Prompt in the results and select Run as administrator.
3. Click Yes if Windows asks for permission.
4. Type exactly: sc stop inpoutx64 and press Enter.
5. Type exactly: sc delete inpoutx64 and press Enter.
6. Open File Explorer (the folder icon in your taskbar, or press Windows + E). Click once in the address bar at the top of the window where it shows your current folder name, type C:\Windows\System32\drivers and press Enter.
7. Scroll through the files and find one called inpoutx64.sys. Delete it. Windows may ask you to confirm administrator access — click through to allow it.
8. Restart your PC.
9. Launch your game. The crashes should be gone.

Update (19 August 2026): Microsoft has now opened a formal investigation. They've listed ARC Raiders, THE FINALS, and MARVEL Tōkon: Fighting Souls as confirmed affected games.

Update (30 August 2026): Microsoft pushed out an automatic fix on 26 August. It stops the inpoutx64 driver loading on any PC that has one of the affected games installed, so the driver can't take the game down with it any more. Home machines get this through Windows Update on their own. Restart your PC and you should be sorted. When the fix applies, Windows shows a message telling you the driver has been disabled, and after that the game launches normally. THE FINALS was fixed separately by Embark Studios in a game update of their own. MARVEL Tōkon: Fighting Souls isn't covered yet and Microsoft is still working on that one.

If your PC is managed by an IT department and the automatic fix hasn't landed on it, use the Command Prompt steps above instead. The sc stop and sc delete commands get you to the same place by hand.

PIN sign-in stops working after every restart

Third problem, spotted on 19 August, and it's the most disruptive of the lot if you're one of the people it lands on. Since KB5121003 went on, some PCs won't accept the PIN at the login screen any more. Windows offers to set up a new one, you do that, and it works. Then you restart the machine and you're locked out again.

Here's what's going on underneath. Windows keeps your PIN as a small credential file rather than the PIN itself, and this update is corrupting that file. Windows spots the damage when it boots, throws the file away and builds a fresh one, and the fresh one goes bad immediately as well. Round and round it goes. That's why setting a new PIN only ever buys you until the next restart.

It isn't happening to everyone. Plenty of machines took the same update and sign in exactly as they did before.

No official fix yet, and Microsoft hasn't publicly acknowledged the problem at all so far. That normally means they're still working out the scale of it.

What to do in the meantime: sign in with your password instead. On the login screen there's a Sign-in options link just below the PIN box. Click it, pick the key icon for your password, and type that. Password sign-in is completely unaffected by this bug. Only the PIN is broken.

One snag worth flagging. A lot of people set a PIN years ago and haven't typed their actual account password since, so they've genuinely forgotten it. If that's you, you can reset it from your phone or another computer at account.microsoft.com, then use the new password to get into your PC. Do that before you next shut down, not after.

And don't remove the update to get your PIN back. Same reasoning as the games problem above: it closes a hole criminals are already using. Typing a password for a week or two is a nuisance, nothing more.

Screens dropping refresh rate, going black, or losing HDR

Two more turned up on 20 August. This is the first of them, and it's the shakiest thing on this page, so I'll say that up front rather than bury it.

People running KB5121003 are reporting monitors quietly dropping to a lower refresh rate than they were set to, screens blanking for a second or two at random, and HDR either switching itself off or coming back looking washed out. WindowsLatest, PCWorld and NotebookCheck have all written it up, and there's a steady trickle of the same complaints on the forums.

Worth checking before you blame the update

If the only symptom is that everything feels slightly less smooth than it did last week, check what refresh rate Windows actually thinks it's running. Minute's work.

1. Right-click on an empty part of your desktop background (not on an icon) and click Display settings.
2. Scroll to the bottom of that page and click Advanced display.
3. If you've got more than one screen, choose the one that's playing up from the drop-down box at the top.
4. Find Choose a refresh rate and click the box beside it. Pick the highest number in the list that your monitor supports. Most ordinary office screens are 60 Hz, most gaming monitors are 144 Hz or higher. If you don't know, the number is usually printed on the box or in the manual.
5. The screen will flicker and Windows will ask whether you can still see it properly. Click Keep changes.

That's ordinary troubleshooting rather than a fix for the bug, but it clears up a fair share of the "everything's felt laggy since the update" cases I get called about. While you're in there, it's worth seeing whether a graphics driver went on at the same time: hold the Windows key and press I, click Windows Update, then Update history, and look at what installed alongside KB5121003.

Update (27 August 2026): A likely cause has emerged. Windows Update installed a new GPU driver on many PCs at the same time as KB5121003, and GPU driver updates break displays far more often than security patches do. If you haven't checked yet, look through update history for an NVIDIA or AMD entry dated 11 August or nearby: hold the Windows key, press I, click Windows Update, then Update history.

If there's a GPU driver in that list, try these:

1. Reset the refresh rate if you haven't done so already. The steps are in the numbered list above.
2. Reinstall the driver. NVIDIA: go to nvidia.com/drivers, find your card, download the latest driver, run it, and choose Clean installation if the option's there. AMD: go to amd.com/support, download AMD Software: Adrenalin Edition, and run it — it'll find your card on its own.
3. Restart your PC once the driver's finished.

If the screen comes back to normal, it was the driver. Job done.

If after all of that it's still going black or HDR is still thoroughly broken, there's nothing left to try yet. September's Patch Tuesday is the most likely point a fix shows up. Sit tight until then.

USB going dead on AMD X470 PCs

The other one from 20 August, and this is a narrow one. It only hits desktop PCs built on an AMD X470 chipset motherboard. That's 2018 and 2019 kit, the boards that went with Ryzen 2000 and 3000 processors: Asus ROG Strix X470, MSI X470 Gaming Plus, Gigabyte X470 Aorus Ultra and their relatives.

If your PC is Intel, or it's a newer AMD board (X570, B550, X670), or it's a laptop, this isn't yours. Skip it.

On the boards it does affect, KB5121003 takes USB out completely. The failure happens during the update's second reboot: the xHCI host controller, the chip that runs every USB port on the board, falls over with a DRIVER_POWER_STATE_FAILURE, error code 0x9F. Everything hanging off it goes at once. Keyboard, mouse, printer, external drives, the lot. Affected owners have been comparing notes on Microsoft's Community Hub, and the pattern is consistent enough that it's clearly the update rather than a run of coincidences.

The likely explanation is that the update changes how Windows moves USB in and out of low power states, and those older AMD boards don't cope with it. That's read off the symptoms, mind. Microsoft hasn't said a word yet.

What to do if this is you

Before anything else, find out whether you've actually got an X470 board. If USB still works and you're just checking after reading this, hold the Windows key and press R, type msinfo32 and press Enter. The line marked BaseBoard Product is your motherboard model. If USB is already dead, the model is printed on the board itself, usually between the memory slots and the processor cooler, and it'll be on the box if you kept it.

If it says X470 and your USB has stopped, the awkward truth is that you can't fix it from inside Windows, because your keyboard and mouse are the very things that have stopped working. Getting the update off a machine in that state means booting into recovery, which is fiddly at the best of times and much worse with nothing to type on. It's not something I'd talk anyone through in a blog post. Ring me instead and we'll sort it.

Teams and Outlook not opening on certain newer laptops

This one is specific to a small group of machines, so most of you can skip past it. The affected laptops are the Surface Laptop 7, Surface Pro 11, and HP OmniBook 3 — the newer thin-and-light Windows laptops that run on a Qualcomm processor rather than the Intel or AMD chips in most PCs.

After KB5121003, Microsoft Teams and the new Outlook won't start on these machines. Click the icon, nothing happens, or they crash immediately and disappear. The traditional desktop apps — Classic Outlook, Word, Excel — are all fine. It's specifically Teams and the modern packaged version of Outlook that's broken.

Microsoft hasn't officially acknowledged this yet. No patch, no timeline, nothing. Rolling back KB5121003 does fix it, but I wouldn't go that route unless the laptop is genuinely unusable. The update covers over 400 security patches — removing it to get an app working is trading rather a lot for convenience. If it's completely unworkable for you, a rollback is the last resort, not the first move.

For now, the practical answer is to use your browser. Teams works at teams.microsoft.com and Outlook works at outlook.com, both fully functional in Chrome, Edge, or Firefox. It's not ideal, but it keeps you working while Microsoft sort it out.

Printing or PDF export stopped working in your business software

WPF stands for Windows Presentation Foundation. Doesn't matter much what it means. The short version is that it's a toolkit Microsoft made available to software developers, and a lot of business software is built on top of it. Not Word or Excel: Microsoft built those themselves using their own internals. WPF turns up in the kind of software a small or medium business might have bought off the shelf or had custom built: stock management systems, reporting tools, invoicing programs, ERP and accounting packages, that sort of thing.

Microsoft confirmed on 27 August that KB5120708, the .NET Framework update that came out alongside this Patch Tuesday, has broken printing and PDF and XPS export in WPF applications. The cause is a bug in how the update handles font subsetting: when the software tries to embed a common font like Calibri into a printed page or a PDF, it hits an error and stops. The whole job fails.

Office is fine. Word prints normally, Excel prints normally. This is specifically WPF-based applications.

If you've updated recently and a piece of business software that used to print or export PDFs without a problem has suddenly stopped working, this is the most likely culprit. It might show as an error message, or the job might just disappear without producing any output.

There is a fix, but it's not one you apply yourself. It's a configuration change inside the application, and it comes with a caveat: it partially disables a security protection as a side effect. That makes it something for your software supplier or IT support to handle, not a tweak to copy off a forum. When you contact them, mention KB5120708 and say it's the WPF printing bug. Those two things will get them straight to the answer without a lot of back and forth.

Microsoft is working on a proper patch. No date yet.

Installation failures and boot loops

This one is more disruptive than most of the other problems on this page. Some machines are failing to install KB5121003 at all; others are getting past installation but then running into boot loops, black screens, unexpected BitLocker recovery prompts, or Secure Boot errors that have never appeared before.

The HP OmniBook X Flip has been the most consistently reported machine, but it isn't the only one. Error codes you might see: 0x800f0845 and 0x800f0922 on the OmniBook, and 0x800f0983, 0xc1900101, and 0xc0430001 on other hardware. If any of those are on your screen, this section covers you.

KB5121003 includes changes to the Secure Boot certificate chain, the list of trusted signatures Windows checks before loading the operating system. Older BIOS versions on some hardware don't handle that change cleanly, and when they don't, the install either stops partway through or appears to complete and then falls apart at the next boot.

One thing that confuses people and isn't a problem: this update reboots your machine twice during installation. That's deliberate. Don't interrupt it, don't hold the power button, don't assume it's frozen. Let it finish both times.

Microsoft hasn't said anything about this officially. No patch, no timeline. Workarounds only for now.

If the update won't install

Clearing the Windows Update download cache and letting it try again from scratch fixes this in a fair number of cases. It takes about five minutes.

1. Hold the Windows key and press R. A small box appears near the bottom-left of the screen.
2. Type services.msc and press Enter. A window called Services opens.
3. Scroll down the list until you find Windows Update. Right-click it and click Stop. Leave the window open.
4. Open File Explorer (the folder icon in your taskbar, or press Windows + E).
5. Click once in the address bar at the top of the window (where it shows your current folder path), type C:\Windows\SoftwareDistribution\Download and press Enter.
6. Press Ctrl + A to select everything in that folder, then press the Delete key. Click Yes if Windows asks you to confirm.
7. Go back to the Services window. Find Windows Update in the list, right-click it, and click Start.
8. Close Services, then open Settings, go to Windows Update, and click Check for updates. Let it download and install fresh.

If it installed but the PC is stuck

If your machine is stuck in a boot loop or refuses to start properly, you need to get into Windows Recovery and take the update off.

If you can still reach the Windows desktop, go to Settings, then System, then Recovery. Under Advanced startup, click Restart now and skip to step 1 below. If Windows won't load at all, you'll need to force it: turn the PC on, and as soon as anything appears on screen (the manufacturer's logo, or the Windows spinning circle), hold the power button down until the machine turns off. Do this twice. On the third power-on, Windows should take you to a blue screen offering repair options rather than trying to start normally.

1. On the blue recovery screen, click Troubleshoot.
2. Click Advanced options.
3. Click Uninstall Updates.
4. Click Uninstall latest quality update. Windows will restart and remove KB5121003.
5. Once the PC has started normally again, go to your manufacturer's support site and search for a BIOS update for your model. An updated BIOS is what lets the machine take KB5121003 without falling over. Without it, reinstalling the update will likely fail the same way.

If you reach the recovery screen and none of the options work, or the process sounds too daunting to attempt on your own, ring me. This is exactly the kind of job that's better done in person.

A preview of what's coming in September

One more thing, and this one isn't a fault. Microsoft put out KB5120998 on 27 August, an optional preview of next month's changes for Windows 11 24H2 and 25H2. It won't install by itself. You only get it if you go and ask for it under Settings, Windows Update, Advanced options, Optional updates. Leave it alone and the same changes land automatically on 8 September with September's Patch Tuesday. That's what I'd do. Preview builds are where the next round of bugs tends to surface first, and you've read this far so you know how that goes.

The change you'll actually notice is the taskbar. You can move it to the top of the screen, or down either side, instead of being stuck along the bottom. Windows 11 has never allowed that without third-party software, so it's a decent bit of housekeeping four years late. The Start menu also drops the "Recommended" heading and calls that section "Recent", which is at least an honest description of what's in it.

Underneath, WMIC has been removed for good. It's the old command-line tool for querying and changing Windows settings, and Microsoft has been winding it down for years. There's a batch of security work as well, including new post-quantum encryption, which will matter a great deal in about a decade and not at all this week.

Should you still install the update?

Yes. The security fixes in this update patch real threats, including CVE-2026-68820, an actively exploited zero-day that security researchers at Check Point traced to North Korea's Lazarus Group. It also closes 42 Critical vulnerabilities across Windows, Word, and Excel. Don't skip it over a false antivirus notification.

The notification is annoying, but harmless.

If something else has gone wrong since the update, or you're seeing errors you can't explain, that's what local computer repair is here for.

Mark

Mark has been fixing computers since the late '90s and went self-employed in 2008. Based in St Helens since 2013, he works evenings and weekends from his home in Laffak — friendly, affordable repairs for PCs, laptops, and Macs. See reviews on Google