Data Migration in Dynamics 365: How to Avoid the Most Costly Mistakes

When finance leaders think of ERP projects, they often underestimate one of the most critical success factors: data migration.

It’s easy to see migration as “just a technical task.” But the truth is, it has massive implications for finance, reporting, operations, and even external stakeholders. Leave it to the end, and you end up with fire drills, poor data quality, and frustrated users. Done well, it can accelerate testing, validate design decisions, and smooth the go-live process.

Here are practical lessons from real-world Dynamics 365 projects that will help you avoid the most common data migration pitfalls.

1. Incorporate Real Migrated Data into Testing

Testing with dummy data hides problems. Real data exposes them.

• Start with a subset of actual data, then expand to a full set during later test phases.
• Using live-like data allows finance and operations teams to spot inconsistencies, errors, or missing scenarios early.

👉 Related reading: ERP Implementation Mistakes to Avoid

2. Run Multiple Dry Runs

Data migration isn’t a one-shot activity — it should be rehearsed repeatedly.

• Each dry run builds confidence and reduces the unknowns.
• Teams learn where the bottlenecks are and refine their process before the real cutover.

3. Define Go-Live Requirements Clearly

Be crystal clear about what data is required at go-live and what can be migrated later.

• Not every dataset needs to be in the system on day one.
• Setting realistic requirements avoids last-minute scope creep and stress.

4. Plan a Data Freeze Date

Users need to know when legacy systems will stop accepting new entries.

• Communicate a data freeze date well in advance.
• Give teams enough time to adjust, reconcile, and prepare for the cutover.

5. Map Legacy to New Data Structures Thoroughly

Moving to Dynamics 365 means adapting to new structures for chart of accounts, vendors, clients, and products.

• Ensure clear mapping rules for all major datasets.
• Validate mappings with business users — not just IT — to avoid surprises later.

👉 Related reading: The Strategic Role of Financial Dimensions

6. Anticipate External Communication Needs

Data migration isn’t only internal.

• For example: if purchase orders are impacted, vendors need to be notified in advance.
• Plan communications early to reduce disruption and build trust with external partners.

7. Limit Transactional Data Migration

More data = more risk.

• Migrate only what’s necessary for continuity and compliance.
• Archive older transactional data in a reference system instead of forcing it into Dynamics 365.

8. Don’t Forget “Non-Financial” Files

It’s not just master and transactional data that matters.

• Files in SharePoint or other systems are often overlooked until the last minute.
• Include them in your migration scope and timeline.

9. Assign Clear Data Owners and Sign-Off

Without clear accountability, data migration drifts into chaos.

• Appoint data owners for each major dataset (e.g., chart of accounts, vendors, clients, products).
• Establish a formal sign-off mechanism to confirm quality and readiness at each stage.
• This ensures accountability and prevents disputes at go-live.

👉 Related reading: Roles and Responsibilities in an ERP Implementation

10. Rehearse the Go-Live Plan Fully

The cutover weekend should feel like muscle memory.

• Define every step of the data migration in the go-live plan.
• Assign owners, timings, and escalation paths.
• Run through the plan multiple times so nothing is left to chance.

Final Thoughts

Data migration in Dynamics 365 isn’t glamorous, but it’s one of the highest-risk areas of any ERP project. Treat it as a strategic workstream, not a technical afterthought.

By incorporating real data early, running dry runs, clarifying requirements, assigning clear data owners, and planning for both internal and external impacts, you’ll dramatically reduce risk and build confidence across the organization.

👉 Want more practical insights on leading a Dynamics 365 project from the finance side? Explore more articles at FitGap Finance.