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Case Study · IT/ITES Services

Large-Scale Microsoft 365 Tenant-to-Tenant Migration

How we unified multiple Microsoft 365 tenants for an IT/ITES enterprise with 5000+ users, enabling seamless collaboration and centralized governance post-acquisitions.

5000+
Users Migrated
Zero
Business Downtime
24/7
Support Coverage
100%
Sign-off Received

Business Background

A large IT/ITES organization with a history of multiple acquisitions was facing challenges in consolidating its Microsoft 365 environment. Each acquisition introduced separate tenants, fragmented collaboration data, and inconsistent security controls, impacting productivity and governance. The organization required a scalable, phased migration approach to unify collaboration platforms while ensuring zero business disruption and continuous user productivity.

Business Challenges

Multiple Microsoft 365 tenants due to frequent acquisitions
Large user base exceeding 5,000+ users with ongoing onboarding
Migration of critical workloads including business-sensitive data
Need for uninterrupted email flow and collaboration during transition
Requirement for round-the-clock support across geographies
Ensuring user satisfaction and formal business sign-off

Scope of Migration

The engagement covered end-to-end migration of Microsoft workloads, including:

  • Exchange Online (mailboxes, calendars, contacts)
  • OneDrive for Business (user data and permissions)
  • SharePoint Online (critical business sites and document libraries)
  • Microsoft Teams (teams, channels, conversations, and files)

Solution & Approach

We designed a phased, batch-based migration strategy aligned with the customer's acquisition roadmap and business priorities. Key elements of the approach included:

  • Detailed pre-migration assessment and batching strategy
  • Incremental and delta synchronization to keep source and target tenants aligned
  • MX cutover executed with minimal disruption to business operations
  • Post-cutover delta sync to ensure no data loss
  • Migration executed in controlled waves to support ongoing acquisitions
  • 24/7 migration and post-migration support model

Execution Highlights

Migrated 5,000+ users in structured batches
Zero data loss across critical workloads
Continuous incremental synchronization until final cutover
Dedicated support during and after MX cutover
Migration program is still ongoing to support future acquisitions

Business Outcomes

Unified Microsoft 365 environment across acquired entities
Seamless collaboration experience for end users
No major incidents or escalations during migration
Improved governance and centralized administration
High user adoption and acceptance

Customer Feedback

The customer provided formal sign-off after each migration phase, expressing full satisfaction with the execution quality, support responsiveness, and overall delivery.

Key Success Metrics

Users Migrated
5,000+
Support Coverage
24/7
Business Downtime
Zero
Sign-off
100%

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