Use this third party tool to convert you ost into pst. this third party OST to PST converter software enable user to convert ost file to pst file. With the help of this utility you can open inaccessible ost file into outlook email client. In addition to PST format, OST file recovery - technician also enables saving the converted file in other popularly used mail file formats, such as DBX, MBOX, MSG, EML, RTF, HTML, and PDF. The most important feature that makes OST to PST suitable for technicians and administrators is the option to 'Compress' or Split' the converted file right before saving it as PST. This feature is very helpful in case of a large OST file, which you want to convert as PST. this have Free version which allow you to see the preview of all convertible emails and can save 25 emails per mailbox at FREE of Cost.