Home How to Thunderbird to Lotus Notes Migration – Convert Thunderbird MBOX to NSF

Thunderbird to Lotus Notes Migration – Convert Thunderbird MBOX to NSF

by Soft2share.com

Mozilla Thunderbird is free. Lotus Notes is not. But still organizations want to migrate from Thunderbird to Lotus Notes. Why?

The short answer is because IBM Notes is secure. It is designed to work on enterprise level only. The two major reasons for this sort of migrations are as follows:

  • Thunderbird is a basic email application. It is for use at a personal level and in various small-scale IT industries. While Lotus Notes is advanced. So advanced that your average technical guy needs a manual to work with Notes for the first few weeks.
  • Another cause is the security. Thunderbird, being an open source software is not so secure. On the other hand, Lotus Notes is built for data security.

Overview – Mozilla Thunderbird & Lotus Notes

IBM Notes, commonly known as Lotus Notes, is software designed to collectively facilitate instant messaging, calendaring, contact management, browsing, task lists, team room, discussion platforms, meeting planning and even more. It is a client-server platform that provides an interface that can be used as an email client. It is mainly preferred due to its powerful security features.

Mozilla Thunderbird was launched in 2003 and has been a popular email client due to its various extensions and themes. Thunderbird stores its emails in MBOX (mailbox) files.

How to Migrate Thunderbird to Lotus Notes Mail Client

There are two steps involved in this email migration:

  1. Convert Thunderbird mailbox into NSF file
  2. Import NSF file in Lotus Notes

The reason why we require to convert Thunderbird files is because of the lack of official migration method. Between the two email clients, not a single one provides any means to carry out conversion. And the presence of different data file formats makes it even worse. Lotus Notes does not support Thunderbird MBOX files. In fact, you cannot import anything in Lotus Notes other than the NSF file. Therefore, it becomes mandatory to convert Thunderbird MBOX to NSF and then import the NSF in IBM Notes application.

Both the steps are discussed below in detail.

Convert Thunderbird mailbox into NSF file

Note: The mentioned method supports automatic detection of Thunderbird database on the machine with Thunderbird installed. However, if you want to convert the files on a different machine, you can export and transfer the Thunderbird MBOX files using this Step.

  • Download the SysTools MBOX to NSF Converter.
  • Run the software and on the welcome screen, click β€œAdd File” button.
  • start mbox to nsf converter
  • Select Thunderbird and choose the β€œDefault Profile configured” option to automatically detect the database of installed Thunderbird client.
  • select thunderbird
  • Proceed to the next window to choose the Thunderbird profile for data migration to Lotus Notes.
select profiles
Note: If you decided to use MBOX files for Thunderbird to Lotus Notes migration, then proceed with the β€œSelect file/folder from local system” option.
  • The tool now displays the content of MBOX file(s) and waits for the user to proceed with desired export option:
    • For converting selective emails, check/uncheck the boxes and right-click to choose the Export option.
    • Else, click on the Export button from the menu bar without selection of emails.
  • preview emails
  • Now, choose the desired file format i.e., NSF and set the destination folder to save the NSF files.
  • select NSF format
  • Apply additional setting to manage the size of converted NSF file by splitting it into smaller files.
  • Click on Export button and enter the password required to access Lotus Notes ID file.
  • enter password of id file
  • The tool successfully converts Thunderbird emails to NSF file format.
  • successful conversion

    Import NSF file in Lotus Notes

    1. Run IBM Notes.
    2. run lotus notes
    3. Click on File from the menu bar and select Import.
    4. menu bar option
    5. Browse the NSF file created earlier and click Import.
    6. browse nsf file
    7. Apply advanced settings as per requirement and click Ok.
    8. import nsf file
    9. The file is successfully imported in Lotus Notes application.

    Now, you can easily view all the emails of Thunderbird in Lotus Notes. This is a simple and effective way to connect Thunderbird to Lotus Notes (figuratively) as all the Thunderbird emails are now accessible in IBM Notes.

    Additional Step [If Required]

    This step aims at exporting all the Thunderbird mailboxes to the computer so it can be used for migration, if the user wishes to do so. This step is not required if conversion takes place on the machine having both Thunderbird and Lotus Notes installed.

    Note: Requires a free add-on so you don’t miss anything: ImportExportTools add-on.

    1. Open Thunderbird.
    2. Right-Click on the email account.
    3. Select ImportExportTools > Export all the folders [with structure].
    4. Choose the location to save the MBOX files and click Select Folder.

    All the folder are successfully exported to computer. The user can simply select the main folder having all the MBOX files and subfolders while using the tool.


    All the facts explained in the article are aimed to ease the process of migrating Thunderbird to Lotus Notes. The defined method is applicable on all Windows version. The first step is to convert the Thunderbird files into NSF format. Then, import the NSF file in Lotus Notes to complete the migration. Additionally, for users who wish to execute the steps on a machine different from the one having Thunderbird installed, steps to extract the Thunderbird mailbox files are also given.

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