From Lotus Notes to Microsoft 365: Lessons from an Enterprise Migration
Enterprise email and collaboration platform migrations are among the most complex and high-stakes IT projects an organisation can undertake. Drawing from direct experience as a core project team member in the UN's migration from Lotus Notes to Microsoft 365, this post outlines the lessons that apply to any enterprise platform migration.
Why Lotus Notes Migrations Are Particularly Complex
Lotus Notes was not just an email platform — it was an application development environment. Organisations that adopted it in the 1990s and 2000s built entire workflows, databases, document management systems, and approval processes directly inside Lotus Notes. Migrating these organisations to Microsoft 365 means not only migrating email and calendars, but also identifying, cataloguing, and recreating or retiring dozens of custom applications built on Notes infrastructure.
This is why organisations still running Lotus Notes tend to underestimate migration scope and timeline dramatically. A rigorous inventory phase before any migration work begins is not optional — it is the foundation of the entire project.
The Five Lessons That Matter Most
Before writing a migration plan, complete a full audit of every Notes database in use — who uses it, how often, and what business process it supports. This inventory will reveal how much is actually being used versus legacy databases that have not been opened in years. Only migrate what is genuinely needed.
The most technically perfect migration fails if users arrive on day one of cutover not knowing how to find their email. Build a structured change management programme: communications well in advance, training resources, and a help desk surge capacity for the first two weeks post-cutover.
Do not cut over and immediately decommission the old system. Run both platforms simultaneously for a defined period, migrate in tranches, and catch issues that only surface in production environments before the point of no return.
There will always be a subset of users — often the least technically confident — who struggle with the new platform long after cutover. Plan for sustained support well beyond the official migration completion date. Cutting support prematurely is one of the most common migration mistakes.
Migrations often focus entirely on email and calendar, but Microsoft 365 includes Teams, SharePoint, OneDrive, Planner, and more. Organisations that migrate email but fail to adopt the broader platform miss significant productivity and collaboration value that justifies the migration effort.
After the Migration: Realising the Value
A Microsoft 365 environment properly configured and adopted gives organisations capabilities that Lotus Notes never could: real-time co-authoring, secure external collaboration, AI-assisted features through Copilot, advanced compliance and data loss prevention tools, and a platform that receives continuous updates from Microsoft.
The investment in migration pays dividends across an organisation's entire operational lifecycle — but only if the migration is managed with the rigour the platform transition deserves.
Craetorian Solutions provides enterprise migration consulting including Lotus Notes to Microsoft 365 transition planning and delivery. Contact us → to discuss your organisation's migration needs.