Updated, 9/15/19, 10am PT: Microsoft officially acknowledged the audio issues caused by the KB4515384 cumulative update on its support website. It offered a workaround for affected users, which we have added to the "How to Fix" section below. Note that this is merely supposed to mitigate the issue; Microsoft expects to have a real fix in late September. Meanwhile, the company explained why this happened with the following statement:
"Microsoft has received reports that audio in certain games is quieter or different than expected after installing this update. At the request of some of our audio partners, we implemented a compatibility change that enabled certain games to query support and render multi-channel audio. Due to customer feedback, we are reverting this change as some games and some devices are not rendering multi-channel audio as expected. This may result in games sounding different than customers are used to and may have missing channels."
Original article, 9/13/19, 8:34am PT:
The complaints about the most recent Windows 10 update haven't stopped. Microsoft released the update on September 10, and by September 12, it was clear the update had failed to address the Windows Desktop Search problems it was specifically made to fix. Windows Latest then discovered that numerous people have complained about the KB4515384 cumulative update causing issues with audio.
These problems appear to vary from person to person. Some claimed the KB4515384 update reset all of their audio settings, others said it led to playback issues while playing games and still others said it caused issues with noise levels. The audio issues aren't the only problems with the KB4515384 update, either, with some people claiming that Screenshots and Snips have an orange tint.
Microsoft acknowledged several of these issues in its support documentation. The orange tint on Screenshots and Snips has been marked "Resolved - External," while the previously reported problems with Windows Desktop Search were marked "Acknowledged." There's nothing about the audio issues yet, but since it took a few days for the Windows Desktop Search issues to appear, that's hardly a surprise.
These continued problems make it harder than ever to convince people that keeping Windows 10 up to date is worth the hassle. Updates have repeatedly caused performance issues, broken important features and otherwise made the experience worse instead of better. Because they contain security upgrades, though, users are left to choose between defending their systems and enjoying them.
How to Fix
Some users said that changing Windows 10's audio settings so the quality is at 16-bit (CD) resolved some of their problems.
Others had to uninstall the KB4515384 update entirely. That can be accomplished by going into the Update & Security page in Settings, heading to View update history and then choosing this release on the Uninstall updates page. At this point, it might be worth memorizing those steps.
Microsoft offered a way to address--but not completely fix--this problem on its support website. "To mitigate the issue, open settings in the impacted game and disable multi-channel audio, if this option is available," the company said. "You can also search in the Windows Control Panel for third-party audio device control panels and disable Multi-channel audio or Virtual Surround Sound, if these options are available."