Opt ost to pst converter free from Vartika software. The ost to pst converter online free tool is the most popular software for OST to Outlook PST Conversion. with this tool user can convert their desired OST file to PST file format at one time. The ost to pst converter open source software to convert Selective items from OST to  PST file. Along with its tool to export OST to PST, Office 365 account, pst file, EML, EMLX, MSG, HTML, MHTML, MBOX, VCF, CSV, ICS, Live, Exchange Server, Zimbra, Gmail, Yahoo, and etc. Users can also save 30 emails per folder free of cost by using this program’s free trial version.