If you're looking to convert a PST file to an OST file, it's important to know that there’s no direct way to convert PST to OST. Use a reliable tool like RecoveryTools OST to PST Converter, because this tool is specifically made for converting OST to PST, not the reverse. As a user, what worked for me was a simple workaround using Outlook itself. I first set up my Exchange or IMAP account in Outlook, which automatically created a new OST file. Then, I imported my PST file into that Outlook profile using the Import/Export feature under the File menu. Once the data was imported, Outlook started syncing it with the mail server, and the OST file was updated with all the emails, contacts, and calendar items from the PST. So, while you can’t convert PST to OST directly using the RecoveryTools OST to PST Converter, Outlook’s built-in features make it possible to achieve the same result by syncing imported PST data into a new OST.