You can try the free solution and convert by opening Microsoft Outlook. But free methods are tricky and also waste users' time. Using this method also reduces the risk of data deletion of Outlook files. Therefore I advise you to use the converter application. you can try the ToolsCrunch OST to PST Converter Tool, I used this tool it is 100% guaranteed to convert OST files to PST files without losing any data. It is the greatest Outlook OST file converter. Users can use this computer application to convert OST files to Outlook PST format, as well as other formats like EML, EMLX, MSG, MBOX, and so on. All attachments from emails, contacts, events, notes, journal tasks, and so on can be extracted by users. It is compatible with Windows OS and Mac.
Read More: https://www.toolscrunch.com/mac-ost-to-pst-converter.html