If your friends can hear your YouTube video, game audio, or system sound through your microphone, the first instinct is usually to reinstall the audio driver.

That is not where I would start.

On Windows 11, "my mic is picking up desktop audio" can mean several different things:

the app is using a loopback source instead of the real microphone

Stereo Mix or a virtual cable is selected somewhere

"Listen to this device" is creating a confusing monitor path

Realtek or headset software is routing audio in a driver layer

a 3.5 mm headset, splitter, or front-panel jack is leaking signal electrically

speakers are simply loud enough that the microphone hears them in the room

Those causes produce almost the same symptom. The fix depends on which path is real.

I published the full version with images and the browser mic test workflow here: Microphone Picking Up Desktop Audio on Windows 11?…