Windows11 System sounds sometimes play through wrong audio endpoint after connecting USB-C dock

You’re seeing system sounds return to the built-in speakers after connecting the USB-C dock, even though the dock is selected, and restarting audio or reconnecting temporarily fixes it. That pattern points to endpoint enumeration or a driver problem rather than ordinary volume settings. In Settings > System > Sound, select the dock under Output. Then open More sound settings > Playback and set it as Default Device and Default Communications Device. Check Volume mixer and ensure System Sounds and apps use Default or the dock, not a speaker override. Install Windows updates plus the PC maker’s USB, chipset, graphics, dock-firmware, and dock-audio updates. In Device Manager, confirm both endpoints remain present after reconnection. Restart Windows Audio and Windows Audio Endpoint Builder only as a diagnostic. Test another USB-C port and cable. If routing still changes, record the dock model, driver versions, and reproduction steps for hardware vendor or Microsoft Support.