Today, we are going to run another How to guide as we normally do on TechAtLast. The focus is on how to remove or delete duplicate contacts in Lotus Notes.
IBM Lotus Notes is an email client that uses the NSF file format as its storage pool where all the information associated with a Notes account gets stored. NSF is an acronym for Notes Storage Facility and it stores its data in a unit refers to as notes. The file names.nsf consists of personal address book information of each account like phone contacts, locations, email addresses, connections, etc.
Many times, duplicate contacts are generated in NSF files of multiple Notes accounts of the employees working in the same organization consuming the unnecessary space of Lotus notes Storage. It is a daunting task to remove duplicate contacts in lotus notes, especially when you are dealing with bulk contacts.
In this tutorial, we are going to discuss different methods and techniques on how to remove duplicate contacts in Lotus Notes. But before moving towards that, let’s understand how duplicate contacts are generated.

How duplicate contacts are generated?
Most of the Lotus Notes user faces problems when their duplicate contacts are generated in the address book. Some causes that lead to the generation of duplicate contacts are listed below:
- When two or more (names.nsf) files of a single account of Lotus Notes are merged to create a single file, then it may generate duplicate contacts.
- When the address book of ex-employee is imported to another employee’s address book working in the same organization, duplicate contacts may be created.
- When the names.nsf file, which is downloaded as an attachment in the Lotus Notes account is synchronized with the contacts already present in the address book, duplicity is likely to occur.
Why Remove Duplicate Contacts in Lotus Notes?
There are many reasons to delete duplicate and identicall contacts that are auto-generated inside IBM Lotus Notes. Some of them are:
- When the contact file size is larger what could be managed. For example, a 20,000 contact list is a headache for the owner.
- Reduction in the speed of the system due to overused storage space.
- Just like the PST file, or Microsoft Outlook data file, the NSF database has a storage limit of 64GB and once this allocation gets filled up, the system begins to malfunction. You can experience data loss as a result of too many files struggling for a limited space.
How to Delete Duplicate Contacts in Lotus Notes
Managing the address book of a Lotus Notes account is a tedious task if the contacts file is large. In addition, duplicate contacts that are generated unintentionally use lots of space that may cause the performance rate of Lotus Notes to slow. Some of the workarounds to remove duplicate contacts in Lotus Notes account are:
Workaround to Remove Duplicate Contacts in Lotus Notes
Step 1. One of the workarounds is to select the duplicate contact individually and delete them to save space. This option is not feasible when there is a large number of contacts present in a single account as it may consume a lot of time.
Step 2. Another method to find the duplicate contacts and delete them is by running Lotus scripts in the Domino agent written by Purna. However, these manual methods do not give satisfactory results and it is very difficult for non-technical people to use the scripts.
Professional Tool for Removing Duplicate Contacts From Lotus Notes
The most effective way to remove the redundant contacts easily from the NSF files is by using a third-party software tool like NSF duplicate remover. The software combine duplicate names.NSF files and generates a single NSF file after comparing the duplicate contact within the files and removing the same contacts. In case of emails also, the tool removes the duplicate emails from Lotus Notes NSF Files.
The software can merge several NSF files of many Lotus Notes accounts at a time, search for duplicate contacts among them, and generate a new NSF file removing the duplicate contacts. The software will first give priority to add the NSF file either by file or folder. The user needs to check the box for Remove duplicate if he/she wants the duplicate contacts to be removed among the multiple NSF files. The saving location where the result will be stored is specified by the user. The tool will provide the new Lotus Notes file where all the contacts from different names.nsf files will be stored without any duplicate contacts. And an additional benefit is you can remove duplicate email in Lotus Notes.
Final Verdict!!
This technical guide focused on How to Delete Duplicate Contacts in Lotus Notes. Both manual methods and professional tools are prescribed. Now it up to to you to choose any of them. Thanks for Reading.
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nice write up , well explained and easy to understand. i was haveing similar issue with my lotus note
i fell into a dilemma when my contact file size began to enter 4000. am not the type of person that easily master things. thank for this
You Aare welcome Stella!
At least with this, you can rest assured of being able to delete duplicate files from your Lotus Notes.
Dan