Lotus Notes Storage Facility (NSF) also known as lotus notes database file it’s a Non-relational database file and is used by IBM Lotus Notes & Domino Software. It stores the data like emails, appointments, documents, and other calendar entries.
Sometimes NSF files got corrupted due to some major factors like:
Some Malware attacks on computer
Sometimes, System got an Abrupt Shutdown.
Hardware component Failure
To avoid the consequences of these Issues I recommend you to use Free NSF Viewer, it’s a tool that allows you to view Lotus Notes Emails, Journals, Contacts, etc.
You can arrange Lotus Notes mail items according to your specific date and Auto-Search option for search specific mail items.