For Converting OST file to PST file you can use this Regain OST to PST Converter Software that can easily Convert your OST file to PST file and other format like: EML, MSG, MBOX, HTML, ICS, VCARD formats. This Software also allows user Export OST file to Office 365 Account and Live Exchange Server. It also support all MS Outlook 2003, 2007, 2010, 2013, 2016, 2019. You can also try this Software free demo version before buy this Software.
I would like to suggest you try one of the top rated OST to PST Converter which is helpful to convert all corrupted, damaged, inaccessible OST file data into readable PST file format and other file formats such as EML, MSG, MBOX, HTML and PDF file formats.
The best OST to PST converter software is Vartika, an all-in-one utility for Windows systems. It ensures full data conversion from Outlook offline OST files such as emails, calendars, contacts, notes, and tasks into outlook PST format. It allows batch conversion, file migration along with attachments, selective email export, file scanning and previewing, and decryption of encrypted offline OST file. It also offers advanced filtering, export options, and a full-featured free demo version.