If you use AWN (avant-window-navigator) you either have already experienced the following, or you are yet to …
When using the Stacks Plugger applet to view mounted volumes, such as flash drives, CD/DVD’s and external Hard Drives, you have to right click on these volumes and select “Unmount Volume” from the right-click menu in order to unmount it. However, right above the “Unmount Volume” option there is another option which is “Hide Volume” and many people will end up at some point mistakingly clicking on that option which makes the volume vanish from AWN but remain mounted. The bothering thing about this is that the next time you plug that same device in it will not show up any more in AWN — VERY annoying!
So here is how to get that undone …
NOTE: You can also accomplish this without the Terminal but its much simpler this way.
STEP 1: Open a Terminal (Gnome: Applications > Accessories > Terminal)
STEP 2: Paste this like into the terminal:
gconftool-2 --recursive-unset /apps/avant-window-navigator/applets
and hit “Enter”.
STEP 3: Close the Terminal and close AWN (Right-click on the corner of the AWN Dock and select “Close”)
STEP 4: Re-open AWN (Gnome: Applications > Accessories > Avant-Window-Navigator)