I would like to mention here OST to PST Migration utility that easily migrates OST to Outlook PST. This software supports all versions, and it efficiently holds data of MS Outlook in an offline folder to access the data without connecting to the internet. The file size is not an issue to get satisfactory conversion results. you can download the free trial version which converts few items from each folder.

More Info:- https://www.spikevare.com/osttopst/

If you don't want to use any third-party software then you can solve your issue related to OST to PST Exportation with the help of a non-manual solution as they are free also. You can avoid the third party software.  The Betavare OST to PST Exporter tool easily Export your data to various OST email Exportation options. Through this tool Recover OST file to safely Exportation OST to PST file with successfully works on exchange OST file version- 2000, 2003, 2007, 2010, and 2013. 2016. It offers a much-anticipated solution for many people who were tired of looking for a direct application, and instead, all they got were inferior OST to PST Exportation tool.  You can check the free preview of OST email Exportation before using this software. And also try the demo version, for your satisfaction.

Visit here:-  https://www.betavare.com/ost/pst/

You should take help of OST to PST Converter that can easily Convert all OST file to PST without any hassle. You can Convert OST file with all emails itmes like contacts, emails, notes, attachments, calendar entries and journals etc. to PST with the help of this OST to PST Converter and You can easily save your OST files in different file formats such as MSG, EML, RTF, HTML, or PDF with this OST Converter tool. Before using full product you can try its free demo version to understand it features and functions.

With this OST to PST Converter open source you can also convert OST file to other formats such as PST, MSG, EML, HTML and Office 365 format. You can split large pst file into small manageable pst files with the help of this OST to PST Converter. You can also convert OST emails items to cloud based Office 365 and Live Exchange Server without any hassle. It GUI is very simple for intense conversion. It provide Free demo version to ensure the users about it functionalities.

You can go with this OST to PST Converter Open Source that can easily convert Contacts, Calendar Entries, Journals and Notes along with Emails from OST to PST without any hassle. This OST to PST Open Source allow the users to select the convertible OST files which you want to convert. OST to PST Convert enable the users to Convert OST files to PST and other formats such as MBOX, PDF, DBX, EML, MSG file and Office 365 format.  It also allow the users to export OST to Office 365 and Live Exchange Server. It also enable the users to split large PST files into Small PST files without any data loss.

After Conversion, OST to PST Converter ask the users to select the destination location to save converted OST files. It GUI is simple and user friendly and allow all users both technical or non technical can easily use this software without have any technical skill. I would like to suggest you to use it free demo version to learn more about it features and functions.