You can not open an NSF file directly in Outlook 2013, 2016 or 2019 because Outlook does not support the NSF format that IBM Notes uses. You need to convert the NSF file into PST format before you can access the contents in Outlook. Using the TrustVare NSF to PST Converter is an easy way to do this. This utility makes it easy for Outlook to open NSF mailbox data such as emails, contacts, attachments and folders by converting them to PST format. It retains the mailbox's original structure, so the data looks the same after it's been converted. The interface is simple to use, so even people who don't know much about computers can do the conversion and then open the PST file in Outlook without any problems.