SYSessential OST to PST Converter is an application developed for Microsoft Windows operating systems that converts offline Outlook files to PST format. The converter offers high-speed bulk and individual OST file conversion without any manual involvement and lets you view your data before converting. SYSessential OST to PST Converter preserves the folder hierarchy of your Outlook offline data file during the conversion process and works on all Outlook versions with its easy-to-use interface.