The Windows Audio Service is not running
1] Check the status of Windows Services
Run services.msc to open the Windows Services Manager . Scroll down to Windows Audio Service and double-click on it to open its Properties. This Service manages audio for Windows-based programs. If this service is stopped, audio devices and effects will not function properly. If this service is disabled, any services that explicitly depend on it will fail to start Set the Startup Type to Automatic and click on the Start button. If it already started, Stop it and then start it again. You should ensure that its Dependency Services are started and have Automatic Startup type: If the Multimedia Class Scheduler Service is present on your system, that too should be Started and set on Automatic. Multimedia Class Scheduler Service (MMCSS) is a Windows service that allows multimedia applications to get prioritized access to CPU for time-sensitive processing (such as multimedia applications) as well as prioritized disc access to ensure that the process is not starved of data to process.
2] Run Playing Audio Troubleshooter
Windows 10 includes the Playing Audio Troubleshooter, which you can easily invoke via the Control Panel, the Taskbar Search or the Troubleshooters tab of our freeware FixWin 10. You can also access it from the Troubleshooters Page in Windows 10. Run it and see if it can fix your problem.
3] Troubleshoot in Clean Boot State
A Clean Boot is used to diagnose and later troubleshoot issues with your system. During a Clean Boot, we start the system with a minimal number of drivers and startup programs which helps isolate the cause with interfering software.
Once you have booted in the Clean Boot State, enable one process after another and see which process makes the problem appear. Thus you can find the offender. See this post if Windows could not start the Windows Audio service on Local Computer.
