Getting “Error 1028: Insufficient Memory” while converting NSF files – How to fix?

ivyclarkharris — Thu, 19 Feb 2026 07:42:59 +0000

"Error 1028: Insufficient Memory" signifies that the system doesn't have the resources to handle a huge mailbox when you try to convert NSF files. This happens a lot with large NSF files.

Before you start the conversion, close all apps that you do not need and restart your computer. Check that you have sufficient free RAM and disk space. For improved speed, utilise a 64 bit system if you can. You might also try dividing up really large NSF files into smaller pieces.

To avoid this problem, use a trustworthy tool like WholeClear NSF Converter. The software can easily handle big NSF files. It keeps the data safe during the conversion process. It also lets you convert a lot of files at once. It doesn't need a lot of system resources to work.

Make sure that the NSF file isn't open in IBM Notes before you start. Also always make a backup copy just in case.

Can I import NSF mail data directly into Office 365 or Outlook 365 account?

roggessteave2427 — Fri, 17 Oct 2025 08:32:10 +0000

Yes, it’s possible to migrate NSF data directly into Office 365. Doing it manually, though, involves a lot of steps (first converting to PST, then importing to O365).

Instead, you can use the eSoftTools NSF to PST Converter Software, which includes a direct “Export NSF to Office 365” feature. You just need to log in to your Office 365 account within the tool, and it uploads all your selected NSF emails, contacts, and calendar entries directly to the mailbox — no intermediate PST file needed.

Read More - Lotus Notes to Office 365 Migration

NSF Converter — BeatMaker Forums

Getting “Error 1028: Insufficient Memory” while converting NSF files – How to fix?

Can I import NSF mail data directly into Office 365 or Outlook 365 account?