All have to stay Mono until we have a working update I guess. Side question has anyone found a decent replacement for MS’s Wireless Display Adapter since they have stopped production. Have tried heaps but none have been as good for the price point.
Recent update unable to get sound from casting specfically surface pro 9 windows 11
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Jackson, Todd
40
Reputation points
Since October 14, 2025—KB5066835 (OS Builds 26200.6899 and 26100.6899) update a 4 surface pro 9 devices which work for the business are unable to produce sound throuch casting to devices specifically Microsoft wireless display adapters.
Has this happened to anybody else?
Windows for business | Windows 365 Business
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Philip Orr 0 Reputation points2025-11-11T21:11:38.0866667+00:00 I found that changing the audio source a few times in succession fixes the issue
So it appears a service called mfd or similar is breaking on boot.I am going to be testing with power saver mode disabled completely
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11 answers
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S.Coughlan 0 Reputation points2025-11-09T14:56:43.3033333+00:00 -
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James Hart Prieto 25 Reputation points2025-11-09T15:10:08.3033333+00:00 We went with screen beam 960’s, still more costly, but a good balance, not sure if they still sell that model though.
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Chris Clementi 1 Reputation point2025-11-12T16:22:30.1566667+00:00 The november update does not resolve this issue.
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Adam N 0 Reputation points2025-11-10T10:34:18.92+00:00 We, as a business (Education environment), are also experiencing this same issue (we have Surface 7 Pro & 9 Pro). I have reports of this issue on W11 devices 22H2 - 24H2, so it's not just this update which should only be present on 24H2 devices. I will test it on other devices when I'm able, but I tried the suggestion of changing from stereo to mono, and it didn't resolve the issue on that device.
I implemented a startup PS script to block and remove KB5066835, and from what I can see that GP has taken effect and removed it from our devices. However, the issue is still very prevalent, which leads me to believe that this issue is deeper than this update, at least for our enviroment.
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Cole Shadbolt 10 Reputation points2025-11-11T12:30:49.98+00:00 Hi, Adam
We too have around 80 Surface pro 9s, in an educational setting. This is causing issues daily for us. swapping to mono works around 50% of the time, but then has to be set agian if a teacher swaps rooms (which is a regular occurrence) We are now using E-Share until its patched, as our 75 inch classroom displays have this built in.
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Joris Van Houte 0 Reputation points2025-11-11T16:15:16.6533333+00:00 I have noticed that if you put the full device in mono before streaming the fix 'sticks'. Then again, I'm using the streaming function only to stream from a surface book 3 to a samsung tv. No special adapters involved
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Adam N 0 Reputation points
2025-11-12T08:19:48.6266667+00:00 Hi Joris, when you say "fully device in mono", what do you mean by that? Just putting the mono slider on?
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Joris Van Houte 0 Reputation points
2025-11-12T08:37:19.88+00:00 Yes, so not in the window of the device you're casting to, but the general sound setting under the system tab
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Adam N 0 Reputation points
2025-11-12T08:33:18.49+00:00 This troubleshooting suggestion may be a complete fluke, but I would be interested to know if it fixes for others.
Device scenario - Recently rebuilt Win11 22H2 Surface 9 Pro with all avalaible updates completed.
Out of the gate, this test device was not able to route audio out of Digital Ouput before these changes. I enabled Mono audio, but this did not fix the issue. My next step was using the Troubleshooter on the "Output devices" under System > Sound > Advanced and selecting Digital Output as the device. The wizard asked if I wanted to turn off "Audio Enhancements" on this device. I said yes, the screen went black, and lo and behold, this device can now route audio through the Digital Output. On the "Troubleshooting has completed" page, the box under "Problems found" - Audio enhancements didn't load - status "Not Fixed".
This leads me to believe that this issue could be a bug with Audio Enhancements / Spatial audio.
If others can try this and provide feedback, that would be invaluable.
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Chris Clementi 1 Reputation point
2025-11-12T20:10:25.99+00:00 I tried this but didn't have any luck. Now the mono solution isn't working for me either at the moment. Now the mono option DID work when I casting directly to the built in miracast in my epson projector. But as soon as I switched back to the Microsoft WDA the audio stopped working again.
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Joris Van Houte 0 Reputation points
2025-11-12T20:23:25.89+00:00 tried this but with no success. after disabling the audio enhancements the digital audio option disappears completely until I disconnect and connect again
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Adam N 0 Reputation points
2025-11-13T07:40:11.98+00:00 I was able to try this troubleshooting step with some other clients yesterday afternoon and I wasn't able to replicate. I guess it was a one-off fluke.
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amin acdc 0 Reputation points2025-11-14T00:36:39.44+00:00 I am an educator at a primary school. This is my biggest problem: I use a Surface Pro 8 with Windows 11 to cast to a Smart TV via the Microsoft Display Adapter. This issue started this month, where the output speaker does not work during casting. It has a major impact on my teaching. I sincerely request Microsoft to resolve this problem immediately. I thought my Surface Pro was broken, so I reset the Surface Pro 8 and wiped all data, but it did not solve my problem.
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Maisarah 20 Reputation points2025-11-14T01:02:36.4766667+00:00 Try this:
Sound While Casting Fix:
- Update/Restart Device
- Make sure your device is up to date and restart it.
- Open Settings
- Click the Start menu and select Settings.
- Go to System
- In Settings, select System.
- Click Sound
- Enable Mono Audio
- Under Output, find the Mono audio toggle and switch it On.
- Update/Restart Device
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Philip Orr 0 Reputation points
2025-11-14T01:06:51.8366667+00:00 this worked for us
Came here to post this lol
But also afterwards we were able to switch it off and continue with stereo sound -
Cole Shadbolt 10 Reputation points
2025-11-14T07:44:40.7266667+00:00 Maisarah, This only works maybe 50% of the time.... We need a real fix from Microsoft and we need it quickly. with 80 Surfaces in our school, Its a constant drain on my resources having to go to 25 or more classrooms a day to try the fixes that only last one day if we are lucky. The only real fix is to drop the Microsoft DA and use an alternative like E-Share etc, Until we get a fix.
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Adam N 0 Reputation points
2025-11-17T15:55:32.85+00:00 Post by Fisher, Kraig on https://dori-uw-1.kuma-moon.com/en-us/answers/questions/5611335/windows-11-24h2-25h2-update-not-working-with-the-m?page=1&orderby=Helpful&comment=answer-12346959&translated=false#newest-answer-comment has provided the best workaround fix me and my users thus far.
"We have found that it is the Dolby APPs that are the problem.
Possible solution: In Services disable the Dobly DAX API service and dolby Fusion API service.
Uninstall the Dolby APPs in terminal using:
Get-AppxPackage dolby | Remove-AppxPackage -AllUsers"
I have simply stopped the Dobly DAX API service instead of attempting to uninstall it.