Seamless Migration from Legacy Systems to Microsoft 365 for a Defence SME
Sector: Defence Industry SME | Capability: Cloud Migration & Business Resilience | Timeframe: 2017
Problem
A Defence SME relied on legacy ICT systems that were unreliable and prone to failure. The company experienced multi-day outages to email and critical business systems, disrupting operations and creating risk for Defence contract delivery. With compliance obligations increasing and the need for business continuity urgent, the company required the resilience and scalability of cloud services.
Solution
Calexi staff led the end-to-end design and delivery of a Microsoft 365 migration. The approach ensured resilience, continuity, and a seamless user experience. Key actions included:
- Architected for growth and compliance, enabling scalability and future alignment with Defence obligations.
- Achieved zero downtime, with migration completed without business disruption.
- Preserved user experience, maintaining existing accounts and credentials to avoid new logins.
- Hybrid Active Directory integration, supporting a smooth transition from legacy systems.
- Staged mailbox migration, beginning with a test group before migrating the full organisation.
- Weekend execution, ensuring continuity and minimal impact on operations.
Results
The migration delivered clear and lasting business benefits:
- Significant resilience uplift, ending disruptive outages.
- Faster collaboration, with seamless access to Microsoft 365 services.
- Rapid expansion into Microsoft services, unlocking new capabilities.
- Improved staff satisfaction, with positive feedback on reliability and ease of use.
- Seamless scalability, enabling the environment to grow with the business.
Related Services
ICT Engineering
Designing and delivering hybrid and cloud architectures that enable secure collaboration and scalability for Defence, government, and enterprise environments.
Systems Administration
Managing identity, patching, and endpoint security across Windows and Microsoft 365 ecosystems to maintain reliability and compliance.
Project Management
Overseeing migration and modernisation projects end-to-end — from planning to post-implementation ensuring minimal disruption and measurable business outcomes.
Proof Points
✓ Zero downtime during cutover
✓ 100% staff adoption
✓ 100% remote work enabled during transition
✓ Hybrid AD integrated and scalable
✓ Faster collaboration reported by users
Tired of outages disrupting your business?
Calexi delivers seamless migrations to Microsoft 365, with zero downtime, 100% adoption, and a stronger security posture. Talk to us today about modernising your environment.