AFTERPAD

To convert OST files to PST, you can use Microsoft Outlook’s built-in export feature or a third-party tool. In Outlook, open the OST file, go to File > Open & Export > Import/Export, choose Export to a file, and select Outlook Data File (.pst). Follow the prompts to choose the folders you want to export and save the PST file. If the OST file is orphaned or inaccessible, use a dedicated OST to PST converter tool for reliable results.
Visit: https://ifixitoday.com/outlook-email-setup/