TL;DR. Global enterprise technology company, enterprise-scale AD environment, 2-week discovery and M365 readiness assessment. Delivered as a Custom Deployment Solution (CDS) document with environment audit, risk register, and migration blueprint.
What was the client environment?
A global enterprise technology company was planning a Microsoft 365 migration and needed a thorough assessment of its Active Directory environment before committing to a migration approach. The company engaged LeadThem Consulting to conduct a comprehensive AD discovery, evaluate migration readiness, and deliver a Custom Deployment Solution (CDS) document with detailed findings and recommendations.
What made this assessment challenging?
Many organizations jump into M365 migrations without fully understanding the state of their Active Directory environment, leading to costly surprises during execution. This client took the right approach by investing in a proper discovery phase first:
- Unknown AD health. The client needed to understand the current state of their Active Directory environment, including replication health, DNS configuration, and potential issues that could impact a migration.
- M365 tenant readiness. Access to the Microsoft 365 tenant was pending during the assessment, requiring the engineer to work in phases by completing the AD assessment first while waiting for cloud environment access.
- Competing priorities. The client's IT team was managing a major outage during the assessment period, limiting their availability for discovery sessions and delaying access provisioning.
- CDS deliverable requirements. The client needed a formal Custom Deployment Solution document that could serve as the blueprint for the actual migration engagement, covering AD architecture, migration approach, risk factors, and detailed recommendations.
How did LeadThem approach the assessment?
Structured discovery process
Days 1-2: Environment access and initial discovery. Connected via VPN and established access to the on-premises environment. Began exploring the Active Directory environment from the jump box, running PowerShell scripts to export AD data including user objects, group memberships, OU structure, and attribute configurations. Held initial discussions with the client's IT team to understand the desired migration outcome.
Days 3-5: Deep AD assessment. Continued investigation of AD health including replication status, DNS configuration, and trust relationships. Exported and analyzed directory data to identify potential migration blockers. Reviewed data for stale objects, inconsistent attributes, and configuration gaps. Began working on the CDS document while waiting for M365 tenant access.
Days 6-8: M365 assessment and CDS completion. Once M365 tenant access was provisioned, assessed the cloud environment configuration. Integrated findings from both on-premises AD and M365 assessments into the CDS deliverable. Documented migration approach, prerequisites, risk factors, and detailed recommendations.
Key findings
- Clean AD foundation. The on-premises Active Directory environment was in good health, with no replication issues, clean DNS, and well-organized OU structure. This is a positive finding that de-risks the migration significantly, as AD replication and DNS problems are two of the most common causes of migration failures.
- Migration readiness confirmed. The assessment confirmed that the client's environment was ready for migration with no blocking issues identified. The CDS document provided a clear path forward with specific prerequisites and configuration steps.
- M365 tenant configuration gaps. The assessment identified specific configurations needed in the M365 tenant before migration could begin, allowing the client to address these proactively rather than discovering them during execution.
What were the results?
LeadThem Consulting delivered a comprehensive Custom Deployment Solution (CDS) document that gave the client complete visibility into AD health, M365 readiness, and a detailed migration blueprint. The assessment confirmed a clean AD foundation with no blocking issues, gave the client confidence to proceed with the migration, and provided their team with the specific prerequisites and configuration steps needed before execution begins. The CDS serves as the authoritative reference document for the migration engagement.
What is in the CDS deliverable?
- Custom Deployment Solution (CDS) document with complete environment assessment
- Active Directory health report including replication and DNS analysis
- Microsoft 365 tenant readiness assessment
- Migration approach and architecture recommendations
- Prerequisites checklist for migration execution
- Risk register with mitigation strategies
Why LeadThem Consulting
The best migrations start with thorough discovery. Too many organizations skip the assessment phase and pay for it during execution with unexpected blockers, rework, and schedule overruns. LeadThem Consulting's structured discovery process and CDS deliverable give organizations the confidence and documentation they need to execute their M365 migration successfully. When the client's team was unavailable due to a production outage, our engineer used the time productively, continuing independent analysis and CDS documentation rather than burning billable hours waiting.
- What is a Custom Deployment Solution (CDS) document?
- A formal pre-migration deliverable produced by LeadThem Consulting that documents the source Active Directory environment, the target M365 tenant configuration, the recommended migration approach, prerequisites, and risk mitigation strategies. The CDS serves as the authoritative reference document for the migration engagement.
- How long does an AD discovery and M365 migration assessment take?
- Two weeks for this engagement: 5 days of AD discovery, then 3 days of M365 tenant assessment and CDS authoring once cloud access was provisioned. Most assessments run 2-3 weeks depending on environment scope and stakeholder availability.
- What does an AD health audit cover?
- Replication status across all domain controllers, DNS configuration, trust relationships, OU structure, stale and orphaned objects, attribute consistency, GPO inventory, and any configuration gaps that could impact migration. Replication and DNS issues are the two most common causes of migration failures, so they get priority.
- Should an organization do an assessment before committing to an M365 migration?
- Yes. Migration projects that skip the discovery phase routinely encounter unexpected blockers during execution: stale users, broken replication, misconfigured DNS, missing prerequisites in the M365 tenant. A 2-3 week assessment catches these before they become schedule slips and budget overruns.
