For conversion from OST files to PST, you can use the Pcinfotools OST to PST Converter. It provides advanced features, like after converting, you can preview the files, and it has a bulk conversion that helps to convert multiple OST files at once, and it supports all versions of Windows and Outlook editions. It can also convert orphaned and corrupted OST files with the emails, contacts, calendars, and attachments into PST format without any data loss or deletion. The utility offers a clean and accurate interface for all users with integrity. A free demo version is available for you without getting the full version.