ATS OST to PST Converter software supports the password-protected or encrypted OST file and convert them into working or accessible PST file of MS Outlook. If you accidentally forget the OST file's password and need to open them, then you can use this software that will copy all emails from OST file into PST file Then, you can easily open those files with MS Outlook. Formats like EML,EMLX,vCal,vCard,MSG,MBOX,PST etc are supported by this tool. 



Read More:  https://www.ayushtech.com/blog-post/microsoft-ost-to-pst-converter.html

You can try OST to PST Converter Application to convert offline OST to PST format. It successfully works for converting OST files to PST and other file formats without initiating any changes or damage. But before you can purchase this utility, you must download its free trial version that will help you convert the first 10 email items into PST format.

Get more here: https://www.sametools.com/convert/ost/

I would like to recommend professional and reliable tool that named is inQuit OST to PST Converter that provides simple to handle GUI and powerful features. It allows you to easily repairs all the errors and recover harmed/encrypted Outlook OST file data into readable PST file including – emails, calendars, tasks, notes, images, deleted emails, appointments, etc. You can split your large sized OST data file into multiple small sizes PST files within a few simple steps. The has multi-saving option that allows you to export OST file into PST, EML, NSF, MSG, MBOX, EMLX, PDF, Office365, Live Exchange, etc. Download the free version to freely convert starting 30 emails per folder. 

Read More: https://www.inquitsoftware.com/en/ost-to-pst-converter.html