Use the CubexSoft NSF Converter, it is a well-known program that converts Lotus Notes to MBOX with all of the emails, formatting, images, among other things. The application is extremely well-designed with cutting-edge features and ease of use so that non-technical people can utilize it with ease. No file size restriction applies while exporting NSF to MBOX format. The program offers strong compatibility with all versions of Lotus Notes and Outlook.