How can users who are not the owner of a virtual mailbox create new subfolders?
Only the owner of a virtual mailbox will have the context menu when right-clicking on a virtual mailbox that they are the owner of. Users granted permissions on a mailbox will not have access to the context menu, which has the following options:
A user who is not the owner, but has access to a virtual mailbox may create subfolders in that mailbox by right-clicking on a message in a mailbox and selecting the "Copy to Folder..." from the context menu.
From the "Quest Software Archive Manager : Copy to Folder" window, navigate to the folder where a new subfolder is required and select the "New Folder" button.