When Outlook is not working, it can be a difficult problem for Outlook users. In that they can't open the OST file and don't export the OST file data into PDF format manually, because the manual method works when Outlook is working. In such a situation, use a reliable tool like
Toolsground OST to PDF Converter for converting OST files to PDF format, whether the files are corrupted or orphaned. It helps you convert multiple or single OST files to PDF format while maintaining folder hierarchy. It has a user-friendly interface and a demo version, which helps you to easily understand it.