If you are looking for a solution that helps to merge and delete duplicate Outlook contacts, then you can go with the FreeViewer Outlook PST Merge Tool (https://www.freeviewer.org/pst/merge.html). This software works the PST file of Outlook 2019, 2016, 2013, 2010, 2007 and other versions.

It allows the user to combine and delete duplicate entries in Outlook contacts (https://www.freeviewer.org/blog/combine-delete-duplicate-entries-in-outlook-contacts/) without loss of data integrity. The tool supports to merge multiple PST files into a single file with all emails, contacts, and calendars.
 

Hello guys

I want to convert XLS to VCF format, 

To merge multiple PST file into single, if you want to merge two or more than two (multiple) Outlook PST file into singe file of any versions of MS Outlook, try Merge PST tool that allows to slecting multiple PST file to merge or combine them into single PST file format without any loss.

https://goo.gl/Xf5Pnu


Thanks & Regards

PST Merge to quickly join, add or merge multiple PST file into single PST file including calendars, contacts and address book and other email items. PST Merge allows to combine multiple PST files such as email folders, address book, contacts, journals, notes, calendars, tasks to one single PST file.

https://gallery.technet.microsoft.com/office/Merge-PST-Files-into-One-420741c3

Download PST Merge software which is smart solution that without any data loss merge multiple PST files in single PST file. This PST Merge tool takes less time in merging process and is one of the safe methods that give the advance option to combine PST files i.e. - Merge PST, Join PST and Merge Contacts as well as you can also Remove Duplicate Items and Exclude Deleted Items from PST file.

Read more at:  PST Merge software
 

If you have multiple PST files and you want to merge them in one PST file, try PST Merge tool to easily complete this task with simple mouse click. It supports both ANSI and UNICODE PST file and merge mulple PST files in one PST file without any data loss.

https://www.g2crowd.com/products/merge-pst-tool/details

If you're using Outlook Email client application where all your email saved in PST or Personal Storage Table file format then these two thechnique Split and Merge will definitely help you to come back from two major issues:

1. When have large size Outlook PST file.
2. When have large number of Outlook PST file in Outlook account to access.  

Split Technique: This technique will help you to break large size size Outlook PST file in some small PST files so that user can use data of large size file easily. 
Merge Technique: It will allow user combine and merge large number of Outlook email files in one single file.

You can take more information about both two technique from the link: Split and Merge Outlook PST file
 

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