M365 to Nextcloud Migration Strategy

Project Overview

I produced a migration strategy and assessment for moving an organization from Microsoft 365 to self-hosted Nextcloud.

The brief covered data sovereignty, cost predictability, GDPR posture, and a practical service-by-service roadmap.

Why Migration Was on the Table

• Need for clearer control over where organizational data lives
• Rising and less predictable Microsoft 365 licensing costs
• GDPR and data-residency pressure on cloud-hosted suites
• Vendor lock-in limiting flexibility
• Paying for unused features while missing others

Technically, the hard parts were coordinating multiple integrated services, large data volumes, user adoption with minimal downtime, and keeping external integrations alive during a cutover.

Strategy I Produced

I framed a phased assessment-first approach:

• Audit of existing M365 usage, dependencies, and data volumes
• User and workflow requirements, plus integration inventory
• Risk analysis and rollback thinking before any cutover
• Service mapping: OneDrive → Nextcloud Files (with Sendent-style desktop sync), Teams → Nextcloud Talk, Exchange calendars/contacts → CalDAV/CardDAV, with Audriga called out for email/calendar tooling where appropriate
• Parallel-operation and gradual user migration as the preferred pattern over a big-bang switch

Outcome

Deliverable was a documented migration framework and roadmap—not a completed cutover. The value was a clear picture of effort, risks, and tool choices so a later implementation could start from evidence rather than guesswork.