Microsoft’s cumulative update KB4512941 has given rise to quite a few bugs, including some that disabled the Windows search and others that caused high CPU usage.

Another issue that users experienced was broken USB Audio 2.0 microphones with multi-channel technology.  On September 13th, Windows 10 KB4516421 was released to address this bug.

The changelog is as follows:

Addresses an issue in which some customers may be unable to use USB Audio 2.0 multi-channel microphones in Voice Recorder and similar apps.

The hotfix is only shipped via Windows Update for consumers and Windows Server Update Services (WSUS) for businesses, and forced installation is not possible.  The fix will be automatically downloaded and installed on devices in which it’s needed.

Source: windowslatest