To convert free OST to PST you should use InFixi OST to PST conversion tool which makes the conversion very quickly and reliably. This OST to PST tool smartly scans and extracts whole information from Exchange OST and place it into a new PST, MSG, EML and HTML file format. It also gives you the power to split a large recovered PST file into small (1GB-5GB) PST files when saving. It supports Outlook versions up to 2013 and Windows OS up to Win8.