There are lots of tools or methods available online but the most likely solution is EmailsGuru OST to PST Converter. It is specialized tool to convert OST file to PST with all data including emails, contacts, calendars, notes, task and all other items. This tool does not only convert OST to PST but also ensure all data integrity, email formatting, preserving attachments and meta data throughout the conversion process. There is no compatibility issue with this tool as it seamlessly works with all versions of Windows Operating Systems and MS Outlook 2024, 21, 19, 16, 13 and all below version. A free trial version also available of this well developed tool.