Use OST2PST Converter free of cost to convert OST files to PST files. Kernel for OST to PST tool is available in free demo version. Using demo version, you can convert and preview data, and save 25 items from each folder too. You would require the licensed version of the software to save all converted items. The software is very easy to operate due to its user-friendly interface and self-explained features. It supports all versions of Outlook.