Legacy CRM Modernisation for a Manufacturing Group — 12-Year-Old System Replaced Without Disruption

"The parallel operation approach is what made this work. People were not forced onto a new system. They moved when they were ready. By the time we switched off the old system, most people had already stopped using it."

— Group IT Director, Pan-European Manufacturing Group

We had tried to replace this system twice before and both attempts failed. Once because of a botched migration and once because the business rejected the new system at go-live. By the time we engaged Celumai, our IT team was managing a system on unsupported software with no mobile access, no API connectivity, and a user interface from 2012. The risk of doing nothing had become greater than the risk of changing.

The 12-year-old system held the complete commercial history of the business. All customer relationships, pricing history, quote records, and activity logs existed only in this system. Two previous modernisation attempts had failed — one due to data migration problems and one due to change management failure. The business had lost confidence in CRM projects entirely.

The previous failures had both been caused by the same mistake: trying to go live with the new system before users were ready for it. We ran a 6-week parallel operation — both systems live simultaneously, with the new system handling new work and the old system available for reference. Users transitioned naturally as they stopped needing the old system.

We implemented Dynamics 365 Sales as the replacement, with a complete historical data migration from the legacy system. The migration was preceded by an 8-week data quality programme that resolved 14 years of accumulated inconsistencies. Mobile deployment gave field sales access they had never had. Power BI dashboards replaced the static legacy reports.

Migration completed on schedule with zero data loss. User adoption reached 87% within six weeks — higher than the legacy system had achieved in 12 years. Mobile adoption by the field sales team gave management visibility into field activity for the first time. The project that had been deferred three times completed without incident.

Is this familiar?

Microsoft Dynamics 365 challenges in Manufacturing — what we see most often

Legacy CRM replacement is one of the highest-risk projects a commercial organisation can undertake. The combination of historical data, embedded processes, and user habits creates a system that is difficult to replace without disruption — which is why so many replacements are deferred.

The organisations that succeed treat data migration and change management as the primary workstreams, not the technical implementation. The new system is usually the easy part. Getting people to trust it enough to abandon the old one is the challenge.

Celumai specialises in legacy CRM modernisation. We bring a structured approach to data migration and change management that addresses the reasons previous attempts typically fail.