0 - (Default.) Enterprise Vault does not assign or update moved mailboxes to existing entries that have the same legacyMbxDN values. Instead, the server produces an event warning.
1 - Makes Enterprise Vault assign new or moved mailboxes to existing archives if the legacyMbxDN values match.
2 - Creates new entries for the new or moved mailboxes and renames any old entries that have matching legacyMbxDN values, by adding timestamps to the legacyMbxDN fields.
Specifies whether, when migrating mailboxes from one Exchange Server to another, Enterprise Vault automatically assigns migrated mailboxes to existing archives. SynchInMigrationMode affects only the association between user mailboxes and archives; it does not affect the association between journal mailboxes and their archives.