If you have to merge multiple PST files and you want to merge them in one PST file, try Merge PST Tool to easily complete this task with a simple mouse click. The tool also has many features like remove duplicate PST file items while merging into single PST formats & you can also get a free preview for all your PST file before merging into a single file.
The manual method is not straightforward; it is a two-step process.
Step 1: Create a New Outlook PST FileOpen Outlook,Click on Home tab, click New Items, click More Items > Outlook Data File.
Browse for the path to save the file, give it a name, and click Ok.
New Outlook PST file is now created.
Step 2: Import Outlook Data to New PST file
In this step, the data from existing PST data files will be transferred to the new file created in Step 1.
Open Outlook, and click on File tab.Click on Open & Export > Import/Export.
Select Import from another program or file; click Next.
Select Outlook Data file (.pst) and click Next.
Browse the PST data file to import and click Next.
Note: Select between the options given in this step as per the need (shown in the screenshot above).
Select the folder(s) you wish to import to the new PST data file.
Note: Don’t forget to checkmark on sub-folder(s) in case of partial selection of folder(s).
Importing from old Outlook PST data file is successful, but Step 2 has to be repeated to complete the migration from multiple PST data files. Above, the data is imported from a single file only, though the iterative count of Step 2 would depend on the number of PST data files you have from which you wish to import data into a single Outlook PST file.
You can also try Merge PST Tool to merge multiple PST files in MS-Outlook. It Combines PST files without any duplicates PST items. It Consolidates various PST files such as Emails, Contacts, Calendars, Tasks, Notes, and all. It merges without any duplicates PST files in MS-Outlook. Demo Version is also available. Supports in all Version of Windows and Outlook. Capable in ANSI and also UNICODE formats.
Visit here for more info: https://www.osttopstapp.com/pst-merge.html
To make you cognizant of the app output before you advance into its complete version, Merge PST Tool. The trial version provided an earlier view of the combined Outlook PST files in a tree-like arrangement.
To know more about: https://www.sametools.com/merge/pst/