This document discusses how to convert an OST file to a PST file format if the OST file becomes corrupted. It provides three potential solutions: 1. Use an OST to PST converter tool to convert the OST file data into an Outlook PST file format, allowing you to regain access to lost emails. 2. If data restoration from the corrupted OST file is not possible manually or through backups, it indicates the data is likely permanently lost due to issues like deletion, corruption from file size limits, malware attacks, or improper management. 3. The recommended solution is to use an OST to PST converter and recovery tool that can scan in basic or advanced modes to restore even encrypted or password protected files