Welcome Jun,
Thanks for reaching out to Microsoft Q&A Forum. I understand that your onboard Realtek audio on the MSI PRO B660M-A DDR4 suddenly stopped working on Windows 11. Realtek no longer appears in Device Manager, and only HDMI audio through your monitor works, even after reinstalling drivers, updating the BIOS and fully removing the Realtek packages.
Could you please confirm:
- Did the audio first stop working before or after the BIOS update?
- Do you have MSI Center, Nahimic or any other audio enhancement software installed, now or before the issue started?
In the meantime, you can try these steps:
1, Check whether Windows still holds a record of the Realtek codec at a lower level.
- Right-click Start, select Terminal (Admin), then run:
pnputil /enum-devices /class Media /disconnected - Look for an Instance ID that starts with HDAUDIO\FUNC_01&VEN_10EC (VEN_10EC is Realtek).
- If you find one, run:
pnputil /remove-device "paste the Instance ID here", then run: pnputil /scan-devices - Restart the PC and check Device Manager again.
2, Check the boot log for device errors.
- Open Event Viewer, then go to Windows Logs > System.
- Select Filter Current Log, choose Kernel-PnP as the event source, then look for errors or warnings that mention HDAUDIO around the time of the last boot.
- Please share the event ID and message if you find one.
Looking forward to your update.