About the User-defined Selections node in the backup selections list

You can create shortcuts to shares and save them as user-defined selections. Use this feature to quickly access shares that have a very long path or that are unavailable when you set up a backup job. A share may be unavailable because the network resources that are used to locate the computer are offline, even though the computer may still be running and available. In some cases this happens because the computer is on the Internet and accessible from within the company's private network, but cannot be located by using just its name or normal browsing methods.