Merge Multiple PST files into one PST files then I would be suggested this
PST Merge. It joins various PST files such as Emails, Contacts, Calendars, Tasks, Notes and all without any duplicates. Merge PST files in all Version of Windows and Outlook formats. Merge PST files in ANSI and also UNICODE formats. Merge PST files with the selected date or any size of PST files. Merge PST files without installing of MS-Outlook.