How to open NSF file wihtout Lotus Noets? I suggest using the most popular and easiest software that's named SysInspire NSF to PST converter Software. with this tool, users can smoothly convert Lotus Notes NSF files to Outlook PST. After conversion you can easily open NSF files without Lotus Notes. But it always requires the Lotus Notes application to convert and recover NSF files. Because it cannot convert and recover NSF files without Outlook.