Can anyone tell me why my VRDB icon disappears from my system tray on a network system?
Could you describe the problem a little more? When does it disappear? Has it ever been there?
It appears once in a great while on my laptop. Mostly it never appears. However on the networked desktop, it is always visible.
Don’t you have the VRDB icon merged with the main avast! icon? In that case, the VRDB icon is visible only when the VRDB is being (re)generated - after it’s done, it’s hidden until the next VRDB update (3 weeks, by default).
To split the icons, there’s an option in the popup menu.
I have not merged them, I am sure. Is there a way to download and reinstall just VRDB?
Well, I don’t really understand the question. VRDB is just a feature of avast! - you cannot “download” it separatelly.
As for the problem…
If you rightclick on the blue avast! icon - isn’t there a VRDB submenu in the popup menu that appears?
Don’t you use some kind of icon-hiding tool?
Try to check the Data\avast4.ini file - in the [VRDB] section, isn’t there anything suspicious there (like, ShowBaloon=0 or anything similar?)
If after following igor suggestions you want to know a little bit more about the avast4.ini file and its settings, take a look here 
Okay guys, here is what I am coming up with.
If I right click, I have no option allowing me to merge or unmerge the icons. Trust me I havew looked numerous times.
When I checked out the avast4.ini file under the VRDB section the only thing I see are two lines.
Line 1: MergeIcons=0
Line 2: Disable=0
From my understanding of the forwarded post, those settings mean do not merge icons and do not diable VRDB.
Any other sugguestions?
Regarding a best information about the posted forum (from Alwil support), I suggest you an uninstall/re-install procedure now… :-\