Ok for those interested, this is the app, it is very quick to make a shortcut in order to unmute all apps, I did this and the associated a shortucut key to it CTRL+ALT+1 for example.
Command is "SoundVolumeView.exe /Unmute AllAppVolume
And I confirm it works if I go back to desktop.
Problem is as said above, it seems in win 8.1 I can launch the shortcut only in desktop, once i am focused on the application (in this case F22) the shortcut is not working, and if I switch back to desktop while in game I can t resume the game, so the problem is not solved.
I read your post but I don't understand your solution to make the shortcut work while in game, could you explain? Or does it exist another way to make the shortcut keys work also while in-game?
Maybe we can sort this problem out