If you are facing any kinds of difficulty with import OST file to PST format, then Recoveryfix OST to PST Converter tool to convert OST files to EML, PST, DBX, MBOX, MSG, TXT, RTF, HTML, MHTML, PDF, DOC, and DOCX.

Supported Versions:

MS Outlook - Office 365, 2021, 2019, 2016, 2013 (both 32 bit and 64 bit), 2010, 2007, 2003, 2002, 2000, 98, 97
Windows OS - Windows 365, 11, 10, 8.1, 8, 7, Vista, XP, 2000, 98, NT, 95 & Windows Server 2022, 2019 & older versions