I had a strange issue recently with a WVD build. The build was based on a custom image built from Windows 10 Enterprise for Virtual Desktop (1903).

This image had a number of customer Line of Business applications installed.

The customer needed to ensure they could redirect the microphone to a particular application for voice recording.

This is where we experienced issues. . . .

The standard Device Redirection options were configured as follows.

On the connecting machine I ensured the RemoteFX Group Policy to allow RDP redirection was enabled.

I then made the relevant changes to the RDP settings of the WVD Host Pool

Add-RdsAccount -DeploymentUrl "https://rdbroker.wvd.microsoft.com"  
Set-RdsHostPool -TenantName <Tenant Name> -Name <Hostpool Name> -CustomRdpProperty "audiomode:i:0;audiocapturemode:i:1; camerastoredirect:s:*;devicestoredirect:s:*" 

All good then yes? . . . Well no.

When logging into the WVD session via the Remote Desktop Client I found that the microphone was not working?!

Weirdly the Remote Audio microphone was showing in Device Manager

But alas no working microphone!

I then checked the Microphone Settings and was treated to this.

So obviously a GPO was blocking access? . . . No, there were no GPOs configured to control this.

Somehow from the master build image this setting had inherited something or was just plain broken.

In order to fix the microphone I opened Local Group Policy and found the following policy

This was noted as Not configured but was obviously causing issues.

So I set the policy to Enabled with Force Allow

Immediately the microphone started working!

A quick test in Voice Recorder and it was confirmed as fixed!

Afterwards I was able to change the policy back to Not Configured, rebooted the machine and the microphone was still working.

James