You can migrate the contents of PST files, choosing to create shortcuts to migrated items, as follows:
If you create shortcuts in mailboxes, then PST Migrator duplicates the folder structure of the PST files under a new, top-level folder in the mailboxes.
If you create shortcuts in PST files to which users still have access, then the users must move the shortcuts to their mailboxes before the shortcuts will work.
If users store new items in a PST file that has been migrated, you can run the migration again at any time, again creating shortcuts to migrated items. PST Migrator will migrate the new items.
You can delete PST files at the end of the migration. If you do this then, obviously, the files are no longer available to users.
If a user has configured Outlook to deliver new mail to a PST file rather than to the mailbox, there will be errors when Outlook next starts, as follows:
The best solution is for users to make sure, before you perform the migration, that mail is not being delivered to PST files.