Recently I got an advance and best solution to can convert my Offline OST Mailbox file to PST file name as the eSoftTools Free OST to PST Converter Software. This product has the capability to save OST file database into all file configuration for example:- EML, EMLX, vCard, PST, MSG, HTML, Office 365, and PST. User can restore any component of the Outlook OST data file such as messages, contacts, schedules, notes, pictures, and many more. Clients can split large size resulted PST file into multiple small parts. It also offers a messages filter option to sort the email items of OST by size or date.