Cigati PST to Office 365 Migrator Tool is one of the safest software which can convert the PST files into Office 365 efficiently. This software helps to remove the duplicate emails. This utility also helps to migrate the Outlook PST files into the office 365 with all kinds of attachments. This software maintains the data integrity and can migrate the multiple PST files multiple times without losing any data.
Source: http://www.cigatisolutions.com/pst-to-office365-migration/