No more audio in taskbar?!

What to do if there's no more volume icon in the taskbar when you see that it's greyed out in the system notifications list?

In my recent case the following solution worked:

• stop the service 'Windows Audio'
• kill explorer.exe
• reopen explorer.exe 

And then the volume icon reappeared on the taskbar again.

I read other cases where reapplying the group polices through

gpupdate /force

within a domain controller based environment also helped to solve the issue. So anyway, there's at least one way...