Using the simple method of eSoftTools OST to PST converter software you can easily reduce the size of OST files in Outlook without any difficulty. First of all, it provides a splitting option that allows you to split a large PST file into multiple small-size PST file in just one click. It can convert OST to PST and 13+ other formats for example Office 365, MBOX, EML, EMLX, MSG, HTML, vCard, YahooMail, IMAP Account, etc. get more information about this tool visit the official site of eSoftTools OST to PST converter software.