An Intel audio driver was incorrectly pushed to devices via Windows Update for a short period of time earlier this week. After receiving reports from users that their audio no longer works, we immediately removed it and started investigating. If your audio broke recently, and you're running Windows 10 version 1803 or above, please check to see if the incorrect driver was installed. To regain audio, we recommend you uninstall the driver.

1. Type Device Manager in the search box
2. Find and expand Sound, video, and game controllers
3. Look for a Realtek device, or a device that has a yellow triangle with an exclamation point
4. Click on the device to select it
5. From the View menu, choose Devices by connection
6. Look at the parent device - this will be called something like "Intel SST Audio Controller" (Intel Smart Sound Technology driver version 09.21.00.3755)
7. Right-click the controller device
8. Choose Properties
9. You should get a dialog like below. Click on the Driver tab as shown.
   
10. If the driver version is 9.21.0.3755, you have the driver that was sent to you incorrectly.
11. Click Uninstall Device. You will get a popup asking if you want to remove the driver too, as shown.
    
12. Check the checkbox as shown, so the driver will be removed.
13. Click Uninstall.
14. When the driver is uninstalled, reboot your system.
15. Your audio (speakers and headphones) should now work.

UPDATE 2018-10-13: Windows Update KB4468550 now removes the driver automatically from systems that received it incorrectly.

Source: If Windows Update sent you Intel Audio Controller version 9.21.0.3755 by mistake, uninstall it s web log

See also: KB4468550 Intel audio driver Update for Windows 10 1709, 1803, 1809 - Windows 10 Forums

Posted By: Brink
14 Oct 2018