City of Abilene Accelerates Secure M365 Migration With CTG After Cyber Attack

“Working with CTG on our migration from Google to Microsoft 365 was a game-changer for us. Not only did they complete the project on time and within budget, but their expertise also ensured a seamless transition with minimal disruption to our operations. Additionally, their ongoing Tiers 2 and 3 support for our network and systems has been invaluable, significantly improving our operational efficiency and stability. Thanks to their partnership, we’ve successfully modernized our IT infrastructure, setting us up for long-term success.”

—Troy Swanson, MBA, CIO/IT Department Director, City of Abilene

The Challenge and Opportunity

The City of Abilene (the City), located in central Texas, initiated a large-scale modernization effort to standardize the use of Microsoft 365 (M365) across the organization. The initiative focused on migrating from Google Workspace to Microsoft Exchange for email and Microsoft SharePoint Online for file storage to improve collaboration, strengthen information governance and security, and retire costly, difficult-to-govern Google Workspace services.

With limited internal bandwidth and migration expertise, the City sought an experienced Microsoft partner. CTG offered the scale and capabilities of a global Microsoft Solutions Partner with local, on-the-ground support in Texas. Our comprehensive migration strategy—including organizational change management to ensure a smooth transition—further solidified the City’s confidence in our approach, resulting in CTG’s selection.

The Solution and Results

In April 2025—one month before the planned project start—a serious ransomware attack forced the City to take internal networks offline. With operations disrupted, the City needed to restore secure employee access as soon as possible. The attack happened on a Friday; by Monday, a CTG executive was onsite to support recovery efforts. Together, we rapidly adapted our migration approach to meet accelerated timelines and minimize downtime.

In parallel, the CTG team conducted the Exchange and SharePoint migrations, each including a thorough discovery and planning phase. We engaged stakeholders across the organization to understand goals, operational workflows, data dependencies, and compliance requirements (HIPAA, CJIS, etc.). An assessment of the Google Workspace environment was performed, including data volumes, application usage, and user accounts and roles. We identified any unsupported data types, applications, and functionalities that required alternative solutions or manual intervention and worked with the City to address them.

Exchange Migration

The CTG team performed the Exchange migration using a proven methodology designed to maintain business continuity and user satisfaction, and a combination of native Microsoft migration tools and third-party tools. The approach included strong security measures to protect data throughout the migration lifecycle.

Our M365 experts designed and configured Exchange, including mail flow and rules, retention policies, anti-SPAM and anti-phishing requirements, and the baseline security standard. We created a coexistence between Google and Exchange to ensure uninterrupted collaboration during the migration, specifically for calendars and compliance reporting. The CTG team provided advisory services throughout the project to help the City improve the M365 tenant’s security.

Although the initial plan included a test migration and several pilot migrations, the cyber attack required an immediate pivot to production. In approximately 8 weeks, the team migrated about 1,450 mailboxes. Our post-migration support—including data validation, support and monitoring, and optimization—has ensured stability, resolved residual issues, and enabled users to fully leverage M365. This foundation allowed the City to quickly restore critical communications with secure, compliant email operations.

SharePoint Migration

In parallel, the team worked to migrate 23 TB of unstructured content from Google to SharePoint and build a scalable information infrastructure with improved governance, clearer navigation, and future scalability. Using ShareGate Migrate and M365 best practices, the team completed the migration in two phases following a pilot to demonstrate SharePoint’s capabilities. Before each phase, the team performed a health check to uncover security gaps and apply recommendations for remediation, leading to an increased security posture.

• Phase 1: Migrated over 100 Google Shared Drives to temporary SharePoint sites to quickly transition to M365 in less than three weeks.

• Phase 2: Created departmental hubs with connected sites for each division, including more than 100 new sites, configured with site-level permissions and modern features such as news, events, search, and hub navigation.

ShareGate played a vital role in allowing us to transfer large data volumes quickly and accurately, preserve folder structures and permissions, and maintain high visibility and control throughout migration with low business disruption.

Change Management and Outcomes

CTG supported both migrations with a change management strategy focused on user education, engagement, and support. This included role-based training programs, communication plans that provided regular updates and established feedback channels, and support mechanisms such as help desk documentation. This approach ensured a smooth transition, reduced impact on daily operations, and enhanced adoption by increasing confidence in the new tools.

With CTG’s migration support, the City has achieved a more secure and collaborative M365 environment. The CTG team enabled:

• Rapid restoration of a secure collaboration environment following the cyberattack

• Improved security posture through health checks, remediation, and governance controls

• Reduced technology spend by retiring Google Workspace services

• Improved employee productivity with modern tools and standard workflows

• A scalable, future-ready SharePoint architecture that strengthens collaboration and governance

With a modernized and resilient M365 environment, the City is now better positioned to provide its residents with reliable and secure services. Based on CTG’s high-quality migration support, the City engaged us to perform a Cybersecurity Maturity Assessment to evaluate their full security posture, identify improvement areas, and develop a roadmap to enhance their security maturity.

This client story highlights how the right combination of expertise, strategy, and technology can create measurable business value. Explore the related solutions below to learn how CTG helps organizations solve complex challenges, improve performance, and accelerate transformation. When you're ready to discuss your challenges and goals, contact us to connect with an expert.