Moving to Microsoft 365 is a strategic priority for many CIOs, but large‑scale migrations from Domino Server, Exchange or mixed environments carry significant risk. A single misstep can lead to data loss, security gaps or failed user adoption.
This checklist offers a structured approach to Microsoft 365 Migration, from assessment through stabilization. It complements our guidance on Domino Migration strategy for CIOs and lessons from avoiding enterprise Email Migration failure.
Pre‑Migration Assessment: Users, Mailboxes and Applications
Start with a comprehensive assessment:
- User and mailbox inventory. Catalog all users, shared mailboxes, distribution groups and resource mailboxes.
- Source platforms. Document which mailboxes reside on Domino, on‑premises Exchange or other systems.
- Application dependencies. Identify Domino applications, third‑party tools and workflows that rely on email or calendar functionality.
- Security and compliance requirements. Map regulatory, retention and data residency requirements that must carry into Microsoft 365.
This assessment naturally overlaps with Domino‑focused work—when Domino is in scope, RockTeam’s Domino consulting and migration services help ensure no application or compliance dependency is missed.
Designing Your Office 365 Migration Architecture
Next, design the target architecture:
- Hybrid or cutover. Decide whether to use a staged hybrid approach or a big‑bang cutover, guided by risk tolerance and complexity.
- Identity and access. Plan Azure AD Connect, SSO, MFA and conditional access to align with zero‑trust goals.
- Security and compliance. Configure DLP, retention labels, eDiscovery and encryption in line with existing policies.
- Coexistence. Address address book, free/busy and mail routing between Domino, Exchange and Microsoft 365 during transition.
Our IT Consulting Services roadmap practice helps unify collaboration, server, network and security into one integrated plan.
Pilot, Coexistence and User Communication
Pilots and communication are essential for de‑risking the migration:
- Pilot groups. Select users and departments that represent different usage patterns and risk profiles.
- Coexistence validation. Test mail flow, calendar sharing, delegated access and mobile experiences across platforms.
- Change communications. Provide clear timelines, training materials and support channels for affected users.
- Feedback loops. Capture pilot feedback and feed insights into production migration plans.
These steps mirror many of the patterns in our Email Migration failure lessons article, which details the most common pitfalls in large‑scale Email Migration Service engagements.
Executing the Microsoft 365 Migration Cutover
When it is time to cut over:
- Technical runbooks. Finalize scripts, sequencing, fallback plans and checklists for migration waves.
- Real‑time monitoring. Watch throughput, error rates and user experience during and immediately after cutover.
- Issue triage. Ensure rapid response teams are ready to handle high‑priority incidents.
For environments with Domino in the mix, RockTeam’s combined Domino Support and Microsoft 365 migration expertise gives you unified accountability across the full stack.
Stabilization, Support and Optimization After Go‑Live
Post‑migration, focus on:
- Stabilization. Address residual issues, performance tuning and security fine‑tuning.
- Support model. Align your Domino Helpdesk and Microsoft 365 support to handle cross‑platform user questions.
- Optimization. Drive adoption of Teams, SharePoint and other services to realize the full value of Microsoft 365.
RockTeam provides an enterprise‑grade Email Migration Service for Office 365, Exchange and Domino, as well as IT Consulting Services and vCISO guidance to secure your new Microsoft 365 environment. Combined with your longer‑term Domino Migration strategy and understanding of Domino Server’s role, this checklist helps you execute migrations with confidence.
