ERP Implementation Success: Mistakes to Avoid & How to Get it Right.

 

Choosing the right ERP system is a major decision, but the value only starts to appear when that system is implemented properly.

 

ERP implementation is the point where plans, requirements and supplier promises are tested against the reality of the business. Processes need to be agreed, data needs to be cleaned and moved, people need to understand new ways of working, and leaders need confidence that the programme is still on track.

 

According to Gartner, by 2027, more than 70% of ERP implementation projects will fail to meet their objectives and intended business outcomes. That figure does not mean the technology itself is always the problem. In many cases, success depends on whether the business has the structure, governance, data, processes and user engagement needed to make the system work in practice.

 

At Optimum PPS, we have supported more than 300 ERP selection, ERP implementation and digital transformation projects across more than 100 organisations. Across that work, one lesson comes through repeatedly. ERP success depends on how well people, processes and systems are aligned around clear business outcomes.

In this guide we set out the eight most common problem areas, with practical guidance on how to prevent them and what to do if you are already in difficulty.

 

 

What is ERP Implementation?

 

ERP implementation is the process of taking a selected Enterprise Resource Planning (ERP) system and making it work properly across the organisation.

 

That includes the technical work, such as configuration, data migration, integrations and testing. It also includes the business change work, such as process design, training, communication, adoption and post-go-live support.

 

A typical ERP implementation includes:

• Project mobilisation and governance
• Solution design and configuration
• Data cleansing and migration
• Integration planning
• Testing and user acceptance
• Training and change management
• Cutover and go-live planning
• Post-go-live stabilisation
• Benefits tracking and optimisation

 

The strongest implementations do not rush into configuration. They start by making sure the business knows what it is trying to achieve, who needs to be involved, what decisions need to be made and where the main risks are likely to appear.

 

 

 

Why ERP Implementations Go Wrong

 

ERP implementations rarely fail because of one major event. They usually drift because of a series of smaller issues that are not tackled early enough. The project starts without a clear handover from selection. The business case becomes vague. Scope expands. Data migration begins too late. Testing gets squeezed to protect the timeline. Training focuses on how to use the system, but not how people’s work will change. Senior leaders receive updates but do not always have enough visibility of risk, readiness or adoption.

 

Over time, those issues create pressure. Teams lose confidence, vendors and internal stakeholders work from different assumptions, and the project starts to feel harder than it should.

 

 

Mistake 1: Treating ERP implementation as an IT project

 

ERP implementation involves technology, but it affects the whole organisation. It changes how people raise orders, approve spending, manage stock, report performance, plan production, serve customers, run finance processes and make decisions. When the project sits too heavily with IT or the software supplier, the wider business can become disconnected from the decisions that shape how the system will actually work.

 

A technically sound system can still disappoint if:

• People do not adopt it
• Processes feel difficult or unclear
• Reports do not give leaders the information they expected
• Teams keep using spreadsheets to fill gaps
• Users do not trust the data

 

How to get it right

 

Treat ERP implementation as a business change programme supported by technology. That means involving the people who understand how the organisation really works, not just the people responsible for the system. Finance, operations, supply chain, IT, HR, customer service, data owners, process owners and senior leaders all have a part to play.

 

At Optimum PPS, our approach is built around people, processes and systems. We use that model because ERP only delivers value when all three areas work together.

• People need clear roles, ownership and confidence.
• Processes need to be understood, improved and agreed.
• Systems need to support the future operating model rather than automate old habits.

 

Case study spotlight: RoSPA

 

For RoSPA, a UK health and safety charity and membership organisation, the challenge was to understand how people, processes and systems needed to work together across training, qualifications, awards, customer information and internal operations.

 

Optimum PPS worked with RoSPA through a project definition workshop, blueprint phase, system selection and implementation support. More than 70% of staff took part in workshops, helping the charity build a clear picture of how information moved across teams, where manual work created pressure and where stronger alignment was needed.

 

Why it matters:

ERP projects can lose value when they are treated as system changes alone. RoSPA’s programme shows how structured engagement with staff and process owners can give the project a much clearer view of operational reality before implementation decisions are made.

 

 

Mistake 2: Recreating old processes in a new system

 

One of the easiest ways to limit ERP value is to rebuild old ways of working in a new system.

Teams know their current processes, so they describe them as requirements. Exceptions, manual checks and workarounds can then become part of the new design, even when they only existed because the old system could not support a better approach.

 

The result is unnecessary complexity. The system may go live, but it carries forward the same frustrations the project was meant to fix.

 

 

How to get it right

 

Use implementation as the opportunity to improve how work flows across the organisation. Before configuration starts, take time to understand:

• Which processes should stay broadly the same
• Which processes need to be improved
• Which variations are genuinely needed
• Which manual checks can be removed
• Which approvals add value
• Which reports and dashboards matter most
• Which workarounds should not be recreated

 

This does not mean forcing every team into the same process for the sake of standardisation. It means making conscious decisions about what will create better control, visibility and efficiency.

 

Key insight

A new ERP system should not become a more expensive version of the old way of working. Implementation is the chance to simplify, standardise and improve where it makes sense.

 

Case study spotlight: Finsbury Food Group

 

For Finsbury Food Group, a UK speciality bakery manufacturer, growth through acquisition had created a complex, multi-site operation with different systems and ways of working.

 

Optimum PPS supported the group through an ERP and business transformation programme, helping standardise processes, reduce reliance on spreadsheets and improve visibility across the end-to-end supply chain. The work also included an optimisation blueprint to help Finsbury continue improving after the initial ERP rollout.

 

Why it matters:

A new ERP system should not simply recreate old processes in a different platform. Finsbury’s project shows the value of using implementation to simplify, standardise and improve how the business works across sites.

 

 

 

Mistake 3: Weak governance and slow decisions

 

ERP projects create a constant flow of decisions. Some are strategic, such as whether to change a process, phase a rollout or protect a piece of scope. Others are more practical, such as who owns a data set, which report is essential for go-live, or how a testing issue should be resolved.

 

Without clear governance, decisions can stall. Risks stay open for too long, workstreams move at different speeds and the project team spends more time chasing answers than moving forward.

 

Good governance gives the project a rhythm. It defines who makes decisions, how issues are escalated, what needs senior attention and how the programme stays aligned to business priorities.

 

How to get it right

Set up governance before the project gains pace. An effective ERP governance model should include a senior steering group, a named executive sponsor, clear decision rights, defined escalation routes, workstream ownership, risk and issue management, scope controls and regular reporting.

The steering group should do more than receive updates. It should challenge progress, remove blockers and make sure the project remains anchored to the business case.

 

Case study spotlight: Growtivation

 

As a UK supplier to the building, landscaping and horticultural sectors, Growtivation needed an ERP implementation that could support a growing product range and a more complex supply chain.

 

Optimum PPS supported Growtivation through requirements gathering, independent ERP selection and implementation of a cloud-based ERP platform. The programme covered solution design, data cleansing, migration, testing, cutover and go-live, with project governance maintained throughout to keep stakeholders, suppliers and delivery activity aligned.

 

Why it matters:

Strong governance gives an ERP project structure and momentum. It helps keep decisions clear, stakeholders aligned and suppliers accountable throughout delivery.

 

 

 

Mistake 4: Leaving data migration too late

 

Data migration can look like a technical task, but it has a direct impact on how well the business can operate after go-live.

 

Many organisations discover data issues later than they should. Product records may be inconsistent, supplier information may be duplicated, customer data may sit across multiple systems, and finance or stock information may not follow a clean structure.

 

If poor data moves into the new ERP system, users quickly lose confidence. The impact is often immediate:

 

• Reports are questioned
• Forecasts are challenged
• Processes slow down
• Teams create spreadsheets to check the system
• Leaders lose confidence in the information they receive
• Adoption suffers

 

Gartner estimates that poor data quality costs organisations at least $12.9 million a year on average. The exact figure will vary by organisation, but the wider point is valid. Poor data creates real cost, real disruption and real frustration.

 

 

How to get it right

 

Start data migration early and treat it as a business workstream. A strong approach should include data ownership by business area, early profiling, cleansing plans, migration rules, reconciliation controls, repeated test cycles and clear sign-off criteria. The organisation also needs to agree what data will move, what will be archived and what standards the new system requires.

 

Data should reflect the future operating model. If processes are changing, the data structure often needs to change as well.

 

Key insight

Data migration should never be left until the end of the project. Clean, trusted data is one of the foundations of ERP adoption, reporting confidence and operational control.

 

 

 

Mistake 5: Cutting back testing to protect the timeline

 

Testing is often squeezed when ERP projects come under time pressure. This can feel practical in the moment, especially when go-live dates are visible and senior stakeholders want progress. In reality, compressed testing pushes risk into the most crucial stage of the project.

 

Testing should prove that the system can support real business activity. That means testing across processes, roles, data, integrations, reports and exceptions. It should also give users enough exposure to build confidence before go-live.

 

 

How to get it right

 

Protect testing from the start and make sure it reflects real operational scenarios. A strong testing plan should include unit testing, system integration testing, end-to-end process testing, user acceptance testing, data migration testing, reporting validation, security testing, cutover rehearsal and defect retesting.

 

Generic test scripts rarely go far enough. A food and drink manufacturer may need to test batch traceability, allergens, expiry dates, production planning, quality holds and customer service processes. A charity may need to test restricted funds, CRM workflows, trustee reporting, case management and service delivery data.

 

Testing and migration need to reflect how the organisation really works, not just whether the system can complete basic transactions.

 

Case study spotlight: CEDO

 

In a multi-site manufacturing environment like CEDO’s, testing needed to prove that the new ERP and supply chain systems could support real operational activity before go-live.

 

As part of the implementation, Optimum PPS supported scenario-based testing across data, integrations and business processes. This helped the project team check that the system could support live business activity, not just complete isolated transactions.

 

Why it matters:

ERP testing needs to reflect how the business actually works. Realistic testing gives users and leaders more confidence that the system, data and processes are ready for go-live.

 

 

Mistake 6: Underestimating change management and training

 

ERP changes the way people work, so training needs to do more than show users which buttons to press.

 

People need to understand why processes are changing, what the new system means for their role and where they fit into the wider flow of information. Without that context, users may follow the training during go-live, then slowly return to familiar workarounds when pressure builds.

 

Prosci’s benchmarking research found that projects with excellent change management were approximately seven times more likely to meet objectives than those with poor change management. They were also nearly five times more likely to stay on or ahead of schedule.

 

 

How to get it right

 

Build change management into the delivery plan from the start. This should include stakeholder engagement, change impact assessments, communication planning, role-based training, super user networks, readiness checks and adoption support after go-live.

 

The best training feels relevant to the user. It uses real tasks, real scenarios and real examples from the organisation, so people can see how their work will change and what support is available.

 

Case study spotlight: Penumbra

 

For Penumbra, an Edinburgh-based mental health charity, ERP implementation involved a major change in how staff accessed information and worked day to day.

 

Optimum PPS worked as an extension of the Penumbra team, supporting governance, delivery, change management and solution management. The programme helped staff build confidence in new mobile and self-service ways of working, reducing reliance on paper information and improving access to service user records.

 

Why it matters:

ERP training should help people understand new ways of working, not just how to use the system. Penumbra’s project shows how practical support and user confidence can turn implementation into meaningful operational change.

 

 

 

Mistake 7: Allowing scope to expand without enough challenge

 

Scope creep happens when the work inside an ERP implementation expands beyond what was originally agreed. It might start with a small extra report, a change to a workflow, an additional integration, a new approval step or a request to include functionality that was meant to come later.

 

On its own, each request can sound reasonable, but every change has a knock-on impact. It can affect configuration, data, testing, training, timelines, cost and user readiness. If those changes are not properly assessed, the project can slowly move away from its original objectives. The team becomes busier but not always closer to go-live.

 

 

How to get it right

 

Create a clear process for managing scope. Every proposed change should be assessed against business value, delivery risk, cost, timeline impact, testing effort, training effort and alignment with the original objectives.

 

The project team should also be clear on what must be delivered for go-live and what can wait until a later phase. This helps protect momentum without ignoring good ideas.

 

This is where independent ERP implementation support can be especially useful. They can challenge whether a change reflects a genuine business need, whether it is solving the right problem, and whether it should happen now or after go-live.

 

 

Mistake 8: Treating go-live as the end of the project

 

Go-live is a major milestone, but it is not the point where ERP value is complete. The weeks after go-live are critical. Users need support, issues need triaged, reports need checked, data needs monitored and leaders need visibility of how the system is bedding in.

 

If the project team steps away too quickly, small issues can start to affect confidence. Workarounds can reappear, data problems can go unresolved and the business may struggle to build on the investment it has made.

 

 

How to get it right

 

Plan stabilisation and optimisation before go-live. A good post-go-live plan should include aftercare support, daily issue triage, clear ownership of fixes, user support channels, data quality monitoring, reporting validation, adoption checks and benefit tracking.

 

The first priority after go-live is stability. Once the system is stable, the focus should move to adoption, improvement and optimisation. Optimum PPS supports ERP projects across the full lifecycle, from requirements gathering and selection through to blueprint, implementation, delivery and optimisation.

 

 

 

What ERP implementation success looks like

 

ERP implementation success should be measured by the value the organisation gains, not only by whether the system goes live.

 

A successful implementation should improve visibility, reduce manual work, strengthen reporting, simplify processes, build user confidence and give leaders better information. It should also create a platform the organisation can keep improving after go-live.

 

Different organisations will measure value in different ways, but the principle stays the same. ERP implementation works best when the system supports how people need to work, how processes need to flow and how leaders need to make decisions.

 

 

 

Why independent ERP implementation support matters

 

ERP vendors and implementation partners play an important role, but their focus is usually tied to their own software, delivery scope and commercial model.

 

Independent ERP support can help you challenge assumptions, keep the project aligned to business outcomes, strengthen governance, protect scope, manage risk, support internal resource gaps and keep decision-making evidence-led.

 

At Optimum PPS we are completely vendor-agnostic. We do not resell ERP software, and we do not have vendor ties that influence our recommendations. Our role is to help your organisation make sound decisions, manage delivery risk and get value from your chosen system.

 

Our experience across platforms including IFS, SAP, Sage X3, QAD, Infor M3, Microsoft Dynamics 365, NetSuite, Acumatica, Oracle and Power BI, to name a few. This gives us broad ERP knowledge alongside sector-specific delivery expertise.

 

 

 

ERP implementation in summary

 

ERP implementation success comes from structure, ownership and practical delivery.

 

The organisations that get ERP right define outcomes clearly, govern the project properly, manage data early, test thoroughly, support users and keep improving after go-live. They also recognise that ERP implementation places real pressure on internal teams, especially when people are trying to deliver a major change programme alongside their day-to-day roles.

 

The mistakes in this guide are avoidable. But they need to be addressed before they become expensive, which means being realistic about internal capacity, making decisions at pace, challenging assumptions and keeping the project focused on business value throughout.

 

At Optimum PPS, we bring extensive experience across ERP, business systems and digital transformation engagements. That means we can help leadership teams see the risks earlier, ask the right questions, challenge assumptions and keep the project focused on business value rather than just system delivery.

 

 

 

 

 

 

FAQs

 

What is ERP implementation?

ERP implementation is the process of designing, configuring, testing, deploying and embedding an Enterprise Resource Planning (ERP) system across an organisation. It includes governance, process design, data migration, integrations, testing, training, go-live and post-go-live support.

 

What makes an ERP implementation successful?

A successful ERP implementation needs clear business objectives, strong governance, realistic planning, clean data, effective testing, user adoption and structured change management. The system must support the organisation’s people, processes and long-term goals.

 

What are the biggest ERP implementation mistakes?

The biggest ERP implementation mistakes include weak governance, unclear scope, poor data migration, limited testing, lack of change management, unrealistic timelines, poor resourcing, excessive customisation and treating go-live as the end of the project.

 

How long does ERP implementation take?

ERP implementation timelines vary depending on organisational size, complexity, number of sites, modules, integrations, data quality and change impact. A focused implementation may take three to six months, while complex multi-site ERP programmes can take much longer and may need phased delivery.

 

Why does ERP data migration matter?

ERP data migration matters because every process, report and decision depends on accurate data. Poor data can undermine user confidence, weaken reporting, disrupt operations and push teams back into spreadsheets and manual workarounds.

 

How do you prevent scope creep in an ERP implementation?

Scope creep can be prevented by defining the project scope early, agreeing decision rights, assessing every change request against business value and delivery risk, and separating essential go-live requirements from improvements that can move into a later optimisation phase.

 

Why use an independent ERP implementation consultant?

An independent ERP implementation consultant gives objective support without software vendor bias. They help clients manage governance, scope, risks, data, testing, change and supplier accountability, while keeping the project aligned to business outcomes.