GNUMail stands as an open-source, cross-platform email client that finds its primary development focus on Mac OS and UNIX-like systems. Powered by GNUstep, this versatile email client offers robust support for POP and IMAP accounts. Moreover, GNUMail comes equipped with comprehensive filtering options that apply to both incoming and outgoing messages. It boasts two native file formats: Maildir, where messages are neatly organized into subdirectories, and Berkley MBOX, a structured email database file. In terms of security, GNUMail prioritizes data protection and employs GnuPG email encryption for enhanced security measures.

While it's a commendable platform, GNUMail unfortunately lacks HTML format support. Additionally, the emergence of more advanced platforms like Outlook has led to a decline in its user base. Consequently, both organizations and individuals are increasingly transferring their mailbox data from GNUMail to Outlook. However, such a migration requires the assistance of a robust migrator tool. The most recommended email converter is Kernel for MBOX to PST.

Below are some guidelines you should adhere to when converting GNUMail's MBOX files to PST format

  1. Open the MBOX converter application.
  2. Begin by selecting the Browse button to upload a folder. Click on brows button to add file
  3. After adding the folder, click the "Finish" button to continue. Locate the folder in your system
  4. Once the scanning process has completed, the mailbox folders will appear on the tool's interface, situated on the left side. Choose a folder from the left panel to access its contents, and subsequently, click the "Save" button to store the file in PST format. Preview of GNUMail
  5. Choose the PST file output format (compatible with MS Outlook) and proceed by clicking the Next button. Select PST file format as saving option
  6. To designate the conversion criteria for the file, choose from the available filter options. For example, you can arrange the data according to date range, recipient address, destination address, subject, or item type. Click "Next" to proceed with the next step in the process. Select the filter option
  7. To handle the converted PST file, you have the option to utilize the "Split" feature. Within the "Split" dropdown menu, you can divide the file into predefined portions. Additionally, you can include a prefix to create a distinctive file name. After making these selections, proceed by clicking the "Next" button. Split the large size PST fileNote: You can choose to use either the split or prefix features in this step, but they are both optional. Feel free to skip this step if you don't need them.
  8. Select the Browse button to specify where you'd like to save the converted file, and then click Finish when you're ready to proceed. Provide destination to the file
  9. The transformed document is stored in the designated destination. Click the OK button to complete the procedure. GNUMail to PST conversion done