The latest version of the macOS sender now includes the virtual audio driver. There is no need to manually download the driver anymore. After being installed and activated, the sender will now show a prompt asking the user to start the audio driver installation. 

If installed successfully, audio should work properly without issues. However, if the target IFP is still silent or unable to forward the audio during screen sharing, follow the troubleshooting instructions below.

Symptom

When screen casting on macOS using AirSync macOS Sender: 

✅ The video is visible on the IFP

❌ The audio is silent on the IFP

Quick checklist 

We recommend performing the following steps first:
 

How audio casting works

To send sound to the IFP, AirSync macOS Sender uses a Virtual Audio Driver to redirect the audio signal.

1. The Reroute
   The AirSync macOS Sender switches your Mac’s Sound Output from the speakers to the Virtual Audio Driver.
   
   
2. The Capture
   The app "listens" to this virtual driver as if it were a microphone to grab the sound and send it to the IFP.
   
   
3. The Result
   Your Mac’s physical speakers will go silent because the sound is being "piped" directly to the IFP.

Give app permissions

The Mac device won't let the AirSync app "grab" the sound unless it is explicitly given permission.

1. Go to the following setting: 
   
   Apple Menu » System Settings » Privacy & Security.
   
   
2. Check two specific lists:
   
   
   1. Screen & System Audio Recording
      Make sure AirSync is toggled ON.
      
      
   2. Microphone
      Make sure AirSync is toggled ON. 
      
      
      
3. Restart the AirSync app after changing these settings.

Check sound output

If the system doesn't "hand off" the sound to the virtual driver, there is nothing for the app to capture and send to the IFP.

1. Start a casting session using AirSync macOS Sender.
2. Open the following setting:
   
   System Settings » Sound » Output. 
   
   
3. Verify that the output automatically switches to the Virtual Audio Driver (e.g., BlackHole).
4. If you still hear audio coming from your MacBook speakers, the auto-switch failed. To fix:
   
   
   1. Manually click on the Virtual Audio Driver name in the list.
   2. Check the Volume. 
      Ensure the Output Volume slider is turned up and not muted.

Test Web vs. App

If you are using the AirSync macOS Sender and it still isn't working, use the AirSync Web Sender to find the root cause.

1. Quit the AirSync macOS Sender.
2. Open the AirSync Web Sender in Google Chrome.
3. Start casting as usual. 
4. Manually set the macOS Sound Output to the Virtual Audio Driver.
   
   
   1. If Web works: 
      The issue is the AirSync macOS Sender App. 
      - Check permissions again.
      
      
   2. If Web fails: 
      The Virtual Audio Driver is likely corrupted. 
       - Restart your Mac, or 
       - Reinstall the driver.