Windows 11 Update Crashing Games? 5 Fixes That Work (2026)

What Is the KB5124010 Game Crash Bug? Microsoft's Confirmed AC-3 Issue

If your games started crashing right after installing the Windows 11 September 22 update, you're not alone — and it's probably not your graphics card. On October 2, 2026, Microsoft confirmed that KB5124010, the optional September preview update for Windows 11, can make applications that decode AC-3 (Dolby Digital) audio crash unexpectedly.

Microsoft's own description of the bug is blunt: "some applications which require the decoding of AC-3 (Dolby Digital) audio might close unexpectedly" after installing KB5124010 and later updates. In some cases the app fails to launch; in others it works fine until a feature like music playback kicks in — then it closes without warning. The kicker: this is a Windows audio-decoder bug, so reinstalling your games or updating GPU drivers will do absolutely nothing.

Which Windows 11 Versions Are Affected? (24H2, 25H2, 26H2)

Microsoft's release health dashboard confirms the bug hits all three current Windows 11 channels:

• Windows 11 24H2 — build 26100.9550
• Windows 11 25H2 — build 26200.9550
• Windows 11 26H2 — build 26300.9550

Windows Server editions are not affected. Modern apps that bundle their own audio decoders (most current Steam titles, Discord, browsers) are fine — the crash hits apps that rely on Windows' built-in AC-3 decoding path, which is exactly what older games and media players do.

Which Games and Apps Crash?

Community reports and tech coverage point to a consistent pattern of affected titles:

• Fallout: New Vegas — crashes on loading screens
• Oblivion — crashes when music or dialogue audio plays
• Fallout 3 — same AC-3 audio trigger
• SimCity 4 — crashes during gameplay
• Battlefield 6 — some players report crashes. mechanism unconfirmed by EA/Microsoft.
• WARDOGS — the WD-L020 launcher error was traced to KB5124010 by Team17 and fixed in WARDOGS Update 0.1.2 (Sept 30, 2026); a separate launcher compatibility issue, not the AC-3 decoder crash described above.
• Media players and productivity apps using the system AC-3 decoder, including innovaphone myApps

Notice the pattern: mostly older games and apps. If your crashing game is a legacy title, this bug jumps to the top of the suspect list.

How to Confirm It's THIS Bug (Not a GPU or Driver Problem)

Before you uninstall anything, spend two minutes confirming the diagnosis. A GPU-driver crash and an AC-3 audio crash look identical from the outside — but the fixes are completely different.

Check Event Viewer for msmpeg2ac3dec.dll

1. Press Win + X and choose Event Viewer.
2. Go to Windows Logs → Application.
3. Look for recent Error entries timestamped when your game crashed.
4. Open one and check the Faulting module field. If it reads msmpeg2ac3dec.dll — that's the Windows AC-3 decoder — you've found your culprit.

Some users also see exception code 0xc0000602 in the crash entry. A caveat worth knowing: Microsoft hasn't officially confirmed that code as definitive, so its absence doesn't rule out the bug. The combination of "KB5124010 installed recently + game using audio + msmpeg2ac3dec.dll crash" is the practical diagnosis.

Quick sanity check: press Win + R, type winver, and compare your build number to the list above. Then check Settings → Windows Update → Update history for KB5124010.

Fix 1 — Change Audio Format to 16-bit/48kHz (Keep Your Update Installed)

If you don't want to touch Windows Update at all, start here. Lowering the audio format sidesteps the broken AC-3 decoding path in many cases, and it's fully reversible.

1. Right-click the speaker icon in the taskbar and choose Sound settings.
2. Click your output device, then open its Properties (or Advanced, depending on the panel).
3. Under Default Format, change it to 16 bit, 48000 Hz.
4. Click Apply, then OK.
5. Also disable Spatial Sound for the device (set to Off).
6. Launch the crashing game and test.

This won't fix every title, but it resolves the crash for a meaningful share of affected games with zero system changes.

Fix 2 — Install LAV Filters (Free AC-3 Decoder Workaround)

The cleanest technical workaround is to give Windows a better AC-3 decoder. LAV Filters 0.83 is a free, open-source set of DirectShow decoders that registers its own AC-3 decoding path, bypassing Microsoft's broken one.

1. Download LAV Filters 0.83 from the official GitHub release page (search "LAV Filters GitHub 0.83").
2. Run the installer as administrator and accept the defaults.
3. Reboot, then launch the crashing game.

LAV Filters is widely trusted in the media-player community and has been confirmed by users to stop the KB5124010 crashes. If you install it, you can keep every Windows update exactly as-is.

Fix 3 — Bethesda Games: Install the Community Crash-Fix Plugin

If your crashing games are Oblivion, Fallout 3, or Fallout: New Vegas, the community has shipped a targeted fix. A Nexus Mods plugin ("Sep 2026 Loading Crash Fix") patches the game's audio handling so it never hits the broken decoder.

1. Download the plugin from Nexus Mods (search the exact name above).
2. Install it through xOBSE (Oblivion), FOSE (Fallout 3), or xNVSE (New Vegas).
3. Launch via the script extender as usual.

One honest warning: this is an unofficial community plugin. Download it only from Nexus Mods and scan it as you would any mod.

Fix 4 — Uninstall KB5124010 (and Stop It Reinstalling)

If nothing else fits, removing the offending update is low-risk for this specific update — KB5124010 is a non-security preview, so uninstalling it doesn't strip any security fixes.

1. Open Settings → Windows Update → Update history.
2. Click Uninstall updates.
3. Find KB5124010 and uninstall it. Reboot.

If the Settings route fails, use the command line as administrator:

wusa /uninstall /kb:5124010

Important: turn "Get the latest updates as soon as they're available" off in Windows Update settings so it doesn't reinstall. Re-enable once Microsoft ships the AC-3 fix.

Warning: updates released after KB5124010 can carry the same buggy code — removing a newer cumulative update would drop security fixes, a much worse trade.

Fix 5 — Wait for the Official Patch (Oct 13 Patch Tuesday Watch)

Microsoft says it's "working on a resolution for a future Windows update." The Insider Preview Beta Build 26220.9606 (October 7) already contains a fix for msmpeg2ac3dec.dll crashes — the production fix is near.

October 13, 2026 is Patch Tuesday. Check Settings → Windows Update tomorrow, install the October cumulative update, and retest your crashing games.

Windows 11 24H2 Home and Pro hit end of support on October 13, 2026 — if you're still on 24H2, upgrading to 25H2 alongside the fix is smart timing.

What NOT to Do (Don't Reinstall Games, Don't Touch GPU Drivers or BIOS)

• Don't reinstall the game. The game is fine — the crash is in Windows' audio decoder.
• Don't reinstall or roll back GPU drivers. Nothing to do with your graphics card.
• Don't touch BIOS, Secure Boot, or TPM settings. It won't help here.
• Don't disable Windows Update permanently. That trades one bug for security holes.

Is This the Same as Other Recent Windows 11 Game Crashes?

• KB5124010 (this bug): games crash to desktop when AC-3 audio decodes.
• KB5129195 (Sep 14): no audio at all through USB devices — see our Windows 11 audio stopped working after KB5129195 fix guide.
• KB5121003 (August): crashes linked to RGB lighting drivers.

Frequently Asked Questions

Why are my games crashing after the Windows 11 update?

The September 22 update (KB5124010) shipped with a broken AC-3 (Dolby Digital) audio decoder. Any game or app that uses Windows' built-in AC-3 decoding — mostly older titles — can crash to desktop. Microsoft confirmed this on October 2, 2026. Check Event Viewer for the faulting module msmpeg2ac3dec.dll to confirm.

How do I fix games crashing on Windows 11 26H2?

Try these in order: (1) lower your audio format to 16-bit/48kHz and disable Spatial Sound, (2) install LAV Filters 0.83 as a replacement AC-3 decoder, (3) for Bethesda games, install the Nexus Mods "Sep 2026 Loading Crash Fix" plugin, (4) uninstall KB5124010, (5) wait for the October 13 Patch Tuesday update, which is expected to include Microsoft's official fix.

What is KB5124010 and should I uninstall it?

KB5124010 is the optional September 22, 2026 preview update for Windows 11. It's a non-security update, so uninstalling it is low-risk — it doesn't remove security fixes. Only uninstall if you've confirmed the AC-3 crash (Event Viewer shows msmpeg2ac3dec.dll); otherwise try the audio-format workaround first.

How do I uninstall KB5124010 on Windows 11?

Go to Settings → Windows Update → Update history → Uninstall updates, find KB5124010, and remove it. As a fallback, run wusa /uninstall /kb:5124010 in an administrator Command Prompt. Then turn off "Get the latest updates as soon as they're available" so it doesn't reinstall.

Which Windows 11 versions are affected by the AC-3 audio bug?

All three current channels: 24H2 (build 26100.9550), 25H2 (build 26200.9550), and 26H2 (build 26300.9550). Windows Server editions are not affected, and modern apps that bundle their own audio decoders are unaffected.

Why do apps close without warning after a Windows update?

The most common cause right now is this KB5124010 bug: the app works normally until it hits a code path that decodes AC-3 audio (music, dialogue, cutscenes), at which point the broken Windows decoder crashes the whole process — with no error message. Confirm via Event Viewer's faulting module field.

When will Microsoft fix the KB5124010 crash bug?

Microsoft says a fix is coming in a future Windows update. The Insider Beta Build 26220.9606 (October 7) already includes the fix, and October 13 Patch Tuesday is the most likely delivery vehicle — install tomorrow's cumulative update and retest your games.

Tested against Microsoft's October 2 release-health confirmation, Insider Beta Build 26220.9606 release notes, and community-verified reports. If Microsoft ships the official fix, this guide will be updated.