Unfortunately, the fix involves a registry hack
Is your sound icon suddenly missing from your Windows Vista system tray!? It was there just a little while ago, but now it’s gone! For some strange reason, many Vista users have to deal with missing volume and network icons on a regular basis!
Even after I upgraded to Windows Vista SP1, my volume and network connection icons would just disappear from the system tray. The funny thing is that if you go to the Taskbar and Start Menu Properties dialog and click on the Notification Area tab, the volume, network, and power icons are all grayed out!
So basically all of my icons in the notification area are missing! Great! So how can you get your volume and network icons back into the system tray? Unfortunately, if the options to check them are grayed out like above in the Notification Area tab, then you have to hack the registry. First, make sure to backup the registry in case something goes wrong.
Now open the registry editor by going to Start and typing in regedit into the Instant http://www.online-tech-tips.com/computer-tips/how-backup-registry/Search box. Go to the Edit menu and click on Find. Search for “IconStreams” and click OK.
After a few moments, you’ll see the following key with two entries on the right hand side: IconStreams and PastIconStream. You want to right-click on both of those and delete them.
In case you can’t find those two keys for some reason, the full registry path to IconStreams is:
Once you delete those two keys from the registry, restart your computer. Usually, all your icons will come back automatically, but if they don’t, just go to the Notification Area tab under Start Menu properties and check off the icons you want to have appear again.
Unfortunately, this problem of the missing icons in Vista happens to me over and over, even after deleting the registry keys. I’m not really sure of any other way to permanently fix the problem, so if you know of another method, please post a comment and enlighten us all!
If you’re having this problem in Windows XP, Windows 7 or Windows 10, check out my article on how to recover the volume icon on those operating systems. Enjoy!