Cloud Sourcing Office 365 for 60,000 employees
Background
A corporate spin-off increases the complexity of existing IT services. When separating an integrated mail infrastructure, the challenge grows further if the migration is embedded into a cloud service such as Exchange Online. The goal was seamless domain separation and parallel modernization into the Microsoft Cloud.
Initial Situation
The scope: 60,000 users, 90,000 mailboxes, and 80,000 archives. An interruption-free migration was essential to ensure business continuity and avoid antitrust risks. Service quality, transparency, and compliance were top priorities.
Key Challenge
The historically evolved mail environment was shaped by M&A activities: dependencies between mailboxes, heterogeneous policies, and technical legacy issues. Transitioning to a cloud platform with limited customization options required clear governance, strict prioritization, and a robust communication and migration strategy.
Implementation
- Enabling & Technical Upgrade: Preparation of tenant separation, identities, hybrid setups, licenses, and policies. Development of cutover and fallback scenarios.
- Mailbox and Archive Migration: Staged migration of 90,000 mailboxes and 80,000 archives to Exchange Online with throttling and bandwidth control, ensuring service continuity.
- Microsoft 365 Rollout: Deployment of Office 365 Pro including Skype for Business, SharePoint Online, and OneDrive for Business. Enablement, communication packages, and support readiness.
We acted as the central point of contact for business units and IT teams, managing the interface to the external infrastructure service provider. Governance boards, migration calendars, and change and risk management ensured predictability and transparency.
Customer Benefits
The migration was completed within the agreed timeframe. Compliance and security were top priorities. Email domain operating costs decreased while service capacity increased. Global, platform-independent access without VPN barriers reduces friction and boosts productivity. With Microsoft 365, the workforce is now future-ready.