Migration to Microsoft 365 completed with no unplanned downtime, with security settings reviewed as part of the project
This comprehensive Office 365 migration project transformed how a mid-sized accounting practice managed their communications and documents. The firm was operating on legacy Exchange 2010 infrastructure that had become increasingly difficult to maintain, with growing concerns about collaboration limitations and security vulnerabilities.
The firm serves approximately 150 clients across Queensland, handling sensitive financial data that required robust security measures and reliable access for all staff members working from different locations.
| Client Profile | Mid-sized accounting practice serving 150+ clients across Queensland |
|---|---|
| Industry | Professional Services — Accounting & Tax |
| Team Size | 12 staff members including accountants, tax specialists, and administrative support |
| Existing Infrastructure | On-premise Exchange 2010 server, aging file server, limited collaboration tools |
| Project Duration | 6 weeks including planning, testing, and production cutover |
| Solution Delivered | Microsoft 365 E3 licences, Exchange Online migration, SharePoint document management, OneDrive personal storage |
The accounting firm faced several critical issues with their existing IT infrastructure. Their on-premise Exchange 2010 server, installed over eight years ago, required increasing maintenance efforts and posed security risks given the software is no longer supported by Microsoft. Staff collaboration was hampered by limited functionality, making it difficult to share documents and work together efficiently on client files.
Additionally, the lack of mobile email access meant staff couldn't respond to urgent client queries while away from their desks, and there were growing concerns about data backup reliability and disaster recovery capabilities. Security was also a major concern, particularly around protecting sensitive client financial information in an increasingly sophisticated threat landscape.
The firm needed a solution that would modernise their infrastructure without disrupting ongoing operations, especially during peak tax seasons when any downtime could have serious business implications.
We designed and executed a comprehensive migration to Microsoft 365 that addressed all identified challenges while providing future-proof infrastructure. Our approach included thorough pre-migration assessment, detailed planning, staged execution, and extensive post-migration support.
Key components of the solution:
We followed a carefully structured implementation methodology to minimise risk and disruption:
Phase 1 — Discovery and Planning (Week 1): Conducted thorough interviews with staff to understand current workflows, documented all custom configurations, identified dependencies between systems, and created detailed migration plans including rollback procedures.
Phase 2 — Preparation (Weeks 2-3): Provisioned the new Microsoft 365 tenant, configured organisational settings, established security policies, set up SharePoint and OneDrive, and performed test migrations with a small group of users to validate the approach.
Phase 3 — Execution (Weeks 4-5): Executed the actual mailbox migration in parallel mode, allowing concurrent use of old and new systems. Ran regular consistency checks to ensure data integrity. On day six, we migrated remaining mailboxes and conducted final validation before cutting over DNS records to point to Exchange Online.
Phase 4 — Go-Live and Support (Week 6): Officially announced the migration to all staff, provided hands-on training sessions, and maintained hypercare support availability during the first week following cutover to address any immediate issues.
The migration achieved all stated objectives with exceptional outcomes:
The firm now enjoys significantly reduced maintenance costs as Microsoft handles all server updates and security patches. Staff can easily collaborate on client files using SharePoint, and everyone has secure mobile access to their email through the Outlook app. The organisation benefits from built-in redundancy and automated backups, substantially improving their disaster recovery posture.
"The migration team's professionalism and attention to detail made this complex project straightforward. We had absolutely no interruption to our client services, and the end result has exceeded our expectations. Our staff are already appreciating the improved tools for collaboration."
Managing Partner, Thompson & Associates