What has worked to me...

 Solution to "No Audio Output Device is Installed" error

Everyone running any Windows OS version is aware of their system gonna be updated periodically. But, what to expect from this "updates".... Sometimes they fix great issues, but sometimes our systems are working really good and these "updates" bring us a really big headache. This post is not intended to describe or to make you learn about what really Windows Updates are, nor trying to get deep into all scenarios where updates work and when not. This post it is just to describe an issue that recently happened to me after a well mentioned update that was applied to my main pc, and also the solution I found it to solve the problem. I hope to bring some help to someone having similar issue and if not, it was a funny time while troubleshooting this and that is why I am here trying to describe it.

Fisrt, a little bit of words... (Reference)

What is the purpose of Windows Update?

Windows Updates allow for fixes to known flaws in Microsoft products and operating systems. The fixes, known as patches, are modifications to software and hardware to help improve performance, reliability, and security.

What happens if updates are not installed?

Your system becomes more susceptible to outside threats when updates are not installed. New malware is released each day and without the security patches from windows updates, your PC is more at risk. Your system could also experience compatibility issues with hardware and software.

Still knowing that regular users can be confused at the time of updating their home pcs or workstations, I would suggest to avoid Automatic system updates.

So, the problem I got...

“No Audio Output Device Is Installed” Error and a red cross over the audio icon into the notification area...

When oppening the sounds settings no audio devices were recognized as active in my system even though I had my speakers on and my headphones plugged in. So, after that I proceed as usually while troubleshooting similar issues before:

- Restart the computer

- Unplug and plug on back again all my audio devices

- Devmgmt.msc to check the involved drivers. All of them were in good shape but I tried to update them anyways comparing versions from the manufacturer website

- Uninstalled the drivers and installed them back again

- Uninstalled the last Windows Update

And probably some other basic steps... but any of these have worked to me this time.

So, after that there is not better way to proceed than going to those pretty good online communities where we can find the most ingenious solutions vs any kind of issue out there, and here we go...

This is what it has worked to me and put me back sound to my workstation.

First of all, open the command prompt (cmd) Run as Admin of course, and type these:

         net localgroup Administrators /add networkservice

         net localgroup Administrators /add localservice

         exit

then, restart the machine and problem should have be gone. Ready, to hear some more noise from my PC ;-) 

Ok, so just hope this quick note can be helpful for somebody as the resolution of the problem was to me, let's keep talking!!!