Repair PST file
As we know, the number of Outlook PST Repair tools are available on the web and it is very hard the say which one is the best solution for converting OST to PST. In the case, I would suggest you try a free trial version of Zaplogix Outlook PST Repair tool that provides a quick, safe, and simple solution to repair corrupted PST files and restore deleted items.
It has offered a FREE DEMO VERSION to users trail purpose and converts 25 items from PST file.
For more Info: https://www.zaplogix.com/outlook-pst-repair.html