Key red flags to consider when moving from SAP ECC6 to S/4HANA

A Guide to Avoiding Pitfalls and Ensuring a Successful Transformation

Introduction

The move from SAP ECC6 to S/4HANA is not a technical upgrade, it’s a strategic business transformation. While SAP positions S/4HANA as a next-generation digital core with real-time processing, streamlined data models, and enhanced user experience, the path to get there is complex. Many organisations make the mistake of treating it as a routine system upgrade, leading to costly delays, budget overruns, and missed opportunities. This article highlights the most common red flags that organisations must be aware of to avoid these pitfalls and ensure a successful transformation to S/4HANA.

Underestimating the Complexity

Red Flag: Treating the move as a simple technical upgrade.

Unlike previous upgrades, S/4HANA involves a complete overhaul of core data structures, business processes, and technical architecture. The simplification of data models and the removal of legacy transactions mean many customisations and processes must be re-evaluated. This is not a “lift and shift”, it’s a transformation.

Mitigation: Conduct a comprehensive assessment early (e.g., SAP Readiness Check, custom code analysis, process impact review) to understand the true scope and effort required.

Lack of Executive Sponsorship and Business Ownership

Red Flag: The programme is perceived as an IT project.

SAP S/4HANA touches every business function, finance, procurement, sales, manufacturing. Without strong executive sponsorship and business leadership, the programme risks misalignment with business goals and resistance to change.

Mitigation: Position S/4HANA as a business-led transformation, with a clear business case, value drivers, and active participation from process owners.

Insufficient Focus on Data Readiness

Red Flag: Data quality and migration are addressed too late in the programme.

Poor data quality is one of the top causes of ERP programme failure. Transforming to S/4HANA involves migrating and reconciling large volumes of master and transactional data, often from fragmented and inconsistent sources.

Mitigation: Start data profiling and cleansing early. Establish a robust data governance model and perform multiple mock migrations using tools like the SAP Migration Cockpit or SAP Data Services.

Custom Code Overload

Red Flag: Large volumes of unused, undocumented, or obsolete custom code in ECC6.

S/4HANA simplifies the data model and architecture, which means many existing custom objects will not function as-is. Retaining unnecessary custom code increases complexity, technical debt, and risk.

Mitigation: Use SAP’s Custom Code Migration Worklist and ATC (ABAP Test Cockpit) to analyse and rationalise code. Decommission what’s no longer needed and adapt critical customisations to fit standard S/4HANA processes where possible.

Not Reimagining Business Processes

Red Flag: Simply replicating ECC processes in SAP S/4HANA without optimisation.

S/4HANA offers significant process improvements (e.g., embedded analytics, real-time reporting, streamlined order-to-cash and procure-to-pay cycles). Replicating outdated ECC processes defeats the purpose of transformation.

Mitigation: Conduct process discovery workshops to assess “fit-to-standard.” Use suitable tools like SAP Best Practices Explorer to identify opportunities to simplify and standardise.

Overlooking Change Management

Red Flag: No structured plan to engage, train, and support end users.

New interfaces, new workflows, and new business logic mean users will need support to adapt. Lack of change management leads to low adoption and operational disruption post go-live.

Mitigation: Develop a formal change and communications strategy. Involve users early, create tailored training, and appoint change champions across business units.

Neglecting Integration Requirements

Red Flag: Assuming existing integrations (to third-party systems, platforms, and databases) will work without change.

The switch to S/4HANA may break existing interfaces due to new APIs, changes in data structures, and platform shifts.

Mitigation: Perform a full integration landscape review early in the programme. Use SAP Integration Suite or middleware to manage changes and build future-proof connectivity.

Inadequate Testing Strategy

Red Flag: Treating testing as a late-stage task focused only on technical validation.

Functional, performance, security, and cutover testing are all critical in an S/4HANA transformation. Without rigorous and iterative testing, defects are often discovered late, putting go-live at risk.

Mitigation: Design a comprehensive test strategy, covering system integration testing (SIT), user acceptance testing (UAT), and multiple cutover rehearsals. Involve business users in scenario-based testing using real data.

Weak Governance and PMO

Red Flag: Lack of structured programme oversight, unclear roles, or scope creep.

S/4HANA programmes can span years, vendors, geographies, and business units. Without strong governance, issues go untracked, timelines slip, and accountability weakens.

Mitigation: Establish a high-performing PMO with clear RACI structures, escalation paths, and milestone tracking. Set up a Design Authority to control scope and design decisions.

Unrealistic Timelines and Budgeting

Red Flag: Setting aggressive timelines without fully understanding programme dependencies.

Rushing to meet fixed deadlines, such as SAP’s ECC6 support end dates, without adequate planning can lead to burnout, compromised quality, and delayed realisation of benefits. While these deadlines are very real and carry significant risk if missed, poor preparation and reactive timelines increase the likelihood of failure.

Mitigation: Base plans on realistic readiness assessments, not just looming deadlines. Include contingencies for complexities in data migration, system integration, and testing to ensure quality delivery under pressure.

Overlooking Cloud Strategy and Hosting Considerations

Red Flag: Deciding on infrastructure (on-premise vs cloud) too late in the programme.

S/4HANA can be deployed in various forms, on-premise, private cloud, public cloud. Each has implications for cost, flexibility, and customisation. Late decisions on hosting architecture can impact performance, security, and integration.

Mitigation: Align your SAP S/4HANA deployment model with your broader cloud strategy. Involve security, infrastructure, and network teams early to avoid rework.

Conclusion

The move from SAP ECC6 to S/4HANA is a critical opportunity to simplify, modernise, and reimagine how your organisation operates. But without foresight, it can also become a high-risk, resource-draining initiative. By proactively addressing the red flags outlined in this document, ranging from data and custom code to governance and change management, organisations can de-risk their programmes and unlock the full value of S/4HANA.

A successful transition requires:

• Strong business ownership
• Realistic planning and governance
• A willingness to challenge legacy thinking
• Investment in people, processes, and data

Ignoring these areas increases the risk of cost overruns, missed benefits, and an ERP that fails to meet the needs of the business.

If you’re shaping your SAP S/4HANA Transformation programme, midway through or facing a recovery, and would like a sounding board, please get in touch, we’d love to talk.