In the case of an orphaned OST file, there are a few manual methods that may help you extract specific items. However, when it comes to reliably converting an OST to PST—especially for retrieving important data like contacts—the most effective solution is using a specialized tool.

One of the top-rated options available is GoldyTools OST to PST Converter. This tool is widely recommended by IT professionals for its ability to recover and convert data from orphaned or inaccessible OST files. It supports multiple output formats and is compatible with various versions of Outlook, including 2007, 2010, 2013, 2016, and even Live Exchange environments.

Whether you're dealing with corrupted files, account issues, or migration needs, GoldyTools provides a user-friendly and efficient way to restore your mailbox data with high accuracy.
https://www.goldytools.com/blog/get-familiar-with-manual-ways-export-import-mails-from-ost-into-outlook-pst/