How to fix output sound on Microsoft Surface Pro 9

Question

This week I have been unable to get sound working through the connection on my Microsoft Surface Pro 9.

Headphones are connecting and working but when I am trying to project my screen to a Commbox (we have tried multiple different ones) the sound will either play out of my computer speakers or not at all. Please let me know if it is possible to fix this.

This problem has not occured before and I have been pairing this computer to Commboxes for over a year.

Answer 1

Hello Annalise, thank you for reaching out to Microsoft Q&A forum.

You might want to check out this recent thread: Recent update unable to get sound from casting specfically surface pro 9 windows 11

It looks like a few users have started noticing similar behavior when casting to devices, and it may be connected to a recent Windows update.

Here are some workarounds you can try:

1. Manually select CommBox as the audio output

• Connect to CommBox using Win + K
• Right-click the speaker icon → Sound settings
• Under Output, select CommBox, Eshare Display, or Wireless Display
• Test the audio

2. Roll back update KB5066835

• Go to Settings > Windows Update > Update history > Uninstall updates
• Remove KB5066835
• Restart your device

3. Enable mono audio

• Go to Settings > Accessibility > Audio
• Turn ON Mono audio
• Reconnect to CommBox and test

I hope this helps fix the issue. If you have any other questions, feel free to ask. 

Warm regards,

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