An old game or media player quitting on its own? Microsoft has found the cause.

If a game or an old media player has started closing itself since late September, you are not imagining it and your PC is not dying. Microsoft confirmed the cause on 2 October.

The culprit is KB5124010, the optional preview update released on 22 September, and anything built on top of it. It breaks the part of Windows that decodes AC-3 audio, better known as Dolby Digital. Programs that hand that job to Windows instead of carrying their own decoder can fail to launch, close without warning, or run perfectly until you do something that plays sound. Microsoft lists games, media players and certain productivity applications as affected, and says Windows 11 24H2, 25H2 and the new 26H2 all carry the bug. We wrote about the same update when it arrived, back when it was the one that fixed File History.

Most modern software ships its own audio decoding and will never notice any of this. The code involved is old, and the apps still leaning on it tend to be old too: a media player you have had for years, a game from a previous console generation, a video editor you open twice a year. That is also why the problem looks so random from outside. Two people on identical machines, one affected and one not, entirely depending on what they happen to run.

There is no patch. Microsoft says a resolution is coming in a future Windows update and nothing more specific than that. The app side is worth checking in the meantime, because a newer version of the player or editor often brings its own decoder and sidesteps the whole thing. Tendvane can run your installed apps through winget and update whatever has fallen behind, which is the quickest way to find out.