If it is mounted as a drive letter then pressing "Show Drives" should show it. Depending on your network conditions, it could take a few seconds (or longer) to show, which is why it isn't displayed by default. Windows Explorer can take just as long, but it is asynchronous, so the dialog is still active and usable while it is trying to ascertain your network connections. This dialog is unfortunately synchronous, so it "blocks" while looking for network connections. Which means the dialog is basically frozen during that time. That could be a very bad experience, so it doesn't do that unless you specifically request it by pressing "Show Drives".