Executive Search & Interim, Industry Insight
By Lee Clarke, Senior Business Director
– Last Updated: May 2026
Most ERP implementations take 18 to 36 months and usually cost significantly more than originally budgeted. The extra cost isn’t because the technology fails – it rarely does – but because the people, planning and governance around it weren’t right from the start. This is the consistent finding from working with organisations across the full ERP programme lifecycle.
ERP implementation typically follows six phases and each carries distinct risks, with the businesses that navigate them well sharing one thing in common: they bring in experienced interim specialists at the right moments, not just when something goes wrong.
This is where programmes are either set up for success or quietly set up to fail. Businesses that rush scoping or rely entirely on internal teams and their system integrator at this stage often spend the next two years correcting the consequences.
The most common risk is selecting an ERP platform that matches the technology vision but doesn’t reflect how the business actually operates. Independent interim specialists – people who have delivered multiple programmes across different environments – catch this early. They bring structure to vendor evaluation, challenge supplier claims, and establish governance frameworks before the real complexity begins.
How specialist ERP Interims Protect the Discovery and Planning Phase
This is where the distance between current-state operations and the target system becomes concrete – and where costly decisions get embedded if the wrong people are in the room.
The most expensive mistake at this phase isn’t configuration. It’s trying to replicate legacy processes in a new system rather than using the ERP as an opportunity to improve them. Experienced interims challenge that instinct. They also draw a clear line between genuine business requirements and habits that have simply accumulated over time – a distinction that can save significant cost further down the programme.
Why ERP Design Phases Fail without the Right Interim Expertise
Data migration is the phase that surprises businesses most. It looks manageable in a project plan. In practice, legacy data is almost never as clean or consistent as expected. Multiple versions of the same customer record, inconsistent naming conventions, fields populated differently across departments – all of it gets carried into the new system if it isn’t dealt with properly here.
Weak data at this stage doesn’t just slow the programme. It undermines the system’s credibility with the people who need to trust it. The organisations that get this right treat data migration as a business decision, not a technical one, and they put dedicated, experienced resource on it rather than treating it as someone’s secondary responsibility.
Why Data is one of the Biggest Risks in ERP Programmes
Building your ERP team? We place experienced interim specialists across every phase of ERP delivery.
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Testing is the last real opportunity to catch problems before they become operational ones. It’s also the phase most likely to get squeezed when delivery is under pressure – which is precisely when the risk of going live with unresolved issues is highest.
Done properly, testing validates not just that the system functions, but that it works in the context of how specific teams actually operate. Finance needs to reconcile cleanly at month-end. Supply chain needs to run without manual fixes. Integrations need to move data accurately under load. These require experienced testing resources, people who understand the business processes as well as the system, not just engineers running scripts.
Why the Right Interim Talent Protects your ERP go-live
If there is one phase that is consistently underestimated, it is this one. ERP programmes don’t fail because the technology doesn’t work. They fail because the people who need to use it every day don’t understand it, don’t trust it, or weren’t properly brought through the change.
Training and change management aren’t soft activities bolted on at the end. They determine whether the investment delivers its intended value. Interim change specialists bring something internal teams often can’t – the combination of ERP delivery experience and the independence to challenge how change is being managed without political constraint.
How Specialist Interims Drive ERP Training and Change Management Adoption
Go-live is the most visible milestone in any ERP programme. It is also the one where preparation either pays off or it doesn’t. There is no room to improvise in the hours and days around cutover. The decisions made then – about what to fix, what to defer, what to escalate – need people behind them who have been in that room before.
Post-implementation stabilisation matters just as much. Getting the system live is one milestone. Getting it to perform as the business needs it to – with confident users, clean data, and reliable reporting – is the one that determines whether the programme was worth it.
ERP go-live and post-implementation: why the hard work starts here
Across all six phases, the same pattern appears. Businesses invest significantly in technology and in their system integrator, but underestimate the value of independent specialists who have delivered programmes like this before.
The capability that experienced ERP interims bring covers the full programme: leadership and governance, functional design, data migration, testing oversight, change management, and post-go-live stabilisation. But the most valuable contribution is often less visible – having someone in the room who has no political stake in the programme and will call out a risk clearly, before it compounds.
If you’re planning an ERP transformation and want to talk through how to structure the right interim team around it, we’re happy to have that conversation. See more about Interim Management here.
If you’re an ERP specialist looking at your next assignment, we’d like to hear from you too.
For organisations planning or running an ERP programme:
Talk to Lee Clarke about the ERP interim market, what’s available, and how to resource each phase effectively.
For ERP specialists:
If you’re looking at your next assignment across discovery, data, testing, change or go-live, we work with organisations across the UK at every stage.
Lee Clarke – Senior Business Director
Technology & Business Transformation
