To break large size Outlook PST into multiple small PST files then I would like to suggest you use MailsDaddy PST Split Tool. It is a great utility, which easily adds and browse single and multiple PST files at a time. The best part of the software is it provides four options for the user’s to split the PST data such as- Split by date, Split by email, Split by size, and Split by folder. By using any option, the user can easily segment the Outlook PST file.