This merge program is capable to customize the merge process by offering several different ways to merge databases. This app allows you to merge PST file data in similar folders or you can create a separate folder for each PST file. It totally depends on users which option they want to choose. You can pick one, two, three or more PST files to merge them together .If you have blank folders, the utility simply removes the blank folders and merge only those folders which contain the database.

Follow this link :- https://www.mailvare.com/free-pst-merge-software/