Removing a, "Disconnected Network Drive"

removing
the key for that share under
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\MountPoints2]
and then logging off and back on cleared it.
The key for your share will look something like this ##SERVER01#SharedFiles

Taken from: http://www.pcreview.co.uk/forums/thread-2420750.php