If you need to convert OST files to PST and regain access to your Outlook data, I highly recommend Quick Migrations OST to PST Converter, one of the most reliable tools for this purpose. This software allows you to migrate multiple OST files in a single click, making the conversion process fast and efficient.

It supports the export of all mailbox items, including emails, sent items, deleted items, drafts, outbox, inbox contacts, calendars, notes, and more. With its intuitive and user-friendly interface, the tool is easy to operate for both technical and non-technical users, ensuring a smooth and hassle-free migration experience.
https://www.goldytools.com/blog/how-to-choose-the-best-ost-to-pst-converter-software/