Mergers and divestments often require organisations to realign their technology and digital infrastructure. One of the most critical enablers of this transformation is the successful migration of domains and Microsoft 365 tenants. These migrations are not just technical milestones, they are strategic inflection points that can either accelerate or hinder business integration and continuity.
🔍 Understanding the Challenge
Whether you're consolidating environments in a merger or separating them in a divestment, the challenges are multifaceted:
- Aligning identity and access management across entities
- Preserving collaboration workflows and data integrity
- Minimising user disruption and downtime
- Ensuring compliance with regulatory and security standards
A successful migration requires a blend of technical precision, stakeholder coordination, and robust change management.
🛠️ Our Migration Framework
We follow a structured, phased approach to ensure migrations are secure, scalable, and aligned with business goals:
📋 1. Discovery and Planning
This phase is foundational. We:
- Inventory Microsoft 365 workloads, Active Directory structures, and server infrastructure
- Identify application dependencies and licensing constraints
- Conduct risk assessments and stakeholder interviews
- Define the scope of consolidation or separation, including branding and domain strategy
🧰 2. Tenant Preparation
We configure the target environment:
- Verify and add domains in the Microsoft 365 Admin Center
- Update DNS records (MX, CNAME, TXT, SRV) for services like Exchange and Teams
- Set up user accounts, assign roles and licenses, and configure security baselines
🔄 3. Data and Service Migration
We migrate:
- Exchange Online: Mailboxes, calendars, contacts
- OneDrive & SharePoint: Files, folders, libraries, and permissions
- Teams: Chat history, configurations, and channel structures
- Active Directory: User accounts, group policies, and file shares
- Applications: Including server-hosted apps and dependent services
We support both user-only and user-plus-device migration models, depending on whether devices are being retained or refreshed.
🔗 4. Coexistence and Cutover
To ensure continuity:
- We implement mail flow redirection and directory sync
- Enable temporary domain sharing where needed
- Communicate proactively with users and provide training
- Schedule cutovers during low-impact windows with rollback plans in place
✅ 5. Post-Migration Optimisation
After the cutover:
- We validate data integrity and service functionality
- Optimise performance and enforce policies
- Provide user support and adoption enablement
- Decommission legacy infrastructure and update documentation
⚠️ Risk Assessment: A Critical Foundation
Risk assessment is embedded throughout the migration lifecycle. It ensures that potential threats are identified, evaluated, and mitigated before they impact operations.
Key components include:
- Asset and Impact Analysis: Cataloguing domains, identities, and applications, and assessing business impact if disrupted.
- Risk Classification: Evaluating likelihood and severity, and prioritising high-risk items for executive review.
- Security Controls Review: Identifying gaps in patching, access control, and endpoint protection.
- Tool-Based Validation: Using platforms like Azure Migrate and Block64 to assess infrastructure readiness and performance.
- Governance and Reporting: Delivering final risk reports with migration readiness scoring, business case analysis, and compliance recommendations.
This proactive approach helps avoid common pitfalls such as data loss, service outages, and compliance breaches.
🏆 Real-World Success Stories
🏨 Seamless Tenant Split Across Hospitality Operations
A global hospitality group required a complete separation of Microsoft 365 and Active Directory environments following a corporate unbundling. The migration was executed remotely, with no on-site presence, and ensured uninterrupted service for staff and guests.
🌍 Multi-Country Domain Migrations
A series of projects across Europe, the UK, and Africa included:
- A 40,000-user domain migration across 11 countries
- A 2,500-user tenant split for a hospitality entity
- A 2,000-user domain and tenant split across 7 countries These projects demanded deep coordination across geographies and time zones, with a focus on compliance and minimal downtime.
🛫 Cross-Tenant Replication and Synchronisation
A complex migration involved:
- Replicating Active Directory objects across tenants
- Pre-staging and synchronising mail, calendar, OneDrive, and Teams data
- Preserving folder structures, permissions, and Teams containers
- Managing password resets and profile renewals with minimal user disruption
🏢 Strategic Scheduling and Stakeholder Alignment
One project avoided migrating finance users during month-end and coordinated with multiple stakeholders across parent and subsidiary entities. The phased migration respected out-of-scope boundaries and ensured infrastructure health and licensing compliance.
🧑💼 Compliance-Driven Decommissioning
In a compliance-sensitive environment, the team:
- Backed up OneDrive and Teams data before decommissioning
- Used remote support tools for user assistance
- Ran licensing reports to optimise costs and identify active users
- Coordinated across multiple countries with strict data retention policies
🌐 Healthcare Sector Migration Across Africa
A healthcare services organisation operating across multiple African countries needed to migrate over 1,400 Exchange mailboxes to Microsoft 365 within three months to meet regulatory deadlines and avoid costly licence renewals. The project involved:
- Aligning infrastructure with European compliance standards
- Managing subscription transitions and tenant preparation
- Delivering the migration on time and within budget, enabling full operational independence
🏁 Conclusion
Domain and tenant migrations are pivotal to the success of mergers and divestments. With the right strategy, tooling, and expertise, organisations can transition smoothly, reduce complexity, and unlock new opportunities for growth.