Enterprise Vault provides the following tools for migrating (importing) the contents of PST files to archives:
Locate and Migrate. This tool locates PST files on users' computers, copies them to a central location, and then migrates them. Unless you have only a few PST files to migrate, Locate and Migrate is likely to require least effort on your part.
Client-driven PST migration. This tool lets you configure users' computers to locate PST files automatically and copy them to a central PST holding folder. Enterprise Vault then migrates the PST file contents from the PST holding folder to Enterprise Vault archives.
Client-driven PST migration is useful in the following situations:
Scripted migration using Policy Manager. This tool is useful for performing bulk migrations of PST files, but you need to collect the PST files in a central location.
PST Migrator wizard-assisted migration. If you have a small number of PST files, this provides a quick and easy way of migrating them to Enterprise Vault.