Regain OST to PST Converter Features: Convert OST File to PST format. Repair inaccessible offline ost file. Convert OST file to PST, EML, MSG, MBOX, HTML, ICS, VCARD format. Export OST E-mails to Office 365 Platform. No file size limit. Easy to use. Support all the latest version of Windows and MS Outlook. 30 Days Moneyback Guarantee. I suggest you to download the free trial version of this application, Install and convert your ost file to pst file. User can see, all convertible e-mails in free trial version in preview items. Note: Outlook E-mail Client should be installed in your system.