Bug No sound in runtime

Using unity today, I noticed that there is no sound at runtime.But if I select the sound file in the project and play it on the inspector,it will sound.
After,I try changing three unity versions and creating new projects, I couldn't get any sound at runtime.
I have no problem listening to music, watching movies and playing games on this computer.

The most likely conflict is caused by Microsoft updating .net and unity, but I don't know how to test it!

 

Unbelievable ,I found problem,I active Mute Audio in game tab. but why this setting share for every project and every unity version?
This design is soooo anti-human.I would never have thought that all unity versions and all projects would share one setting.This took me half a day.