Moving from SAP ECC or a legacy ERP to S/4HANA is as much an organisational change as a technical one. Across our ERP engagements, four issues consistently cause delays and budget overruns.
1. Custom code you forgot you had
Long-running ERP systems accumulate custom reports, enhancements and interfaces. Many are no longer used, and many will not work on S/4HANA without changes. Running a custom code analysis early — and retiring what nobody uses — can remove a large share of remediation effort.
2. Master data quality
Duplicate vendors, inconsistent units of measure and incomplete material records do not disappear in a new system; they become more visible. Business partner conversion in particular fails on poor data. Budget for a dedicated data clean-up stream with business owners, not just IT.
3. User adoption
Fiori apps and new processes change how people work every day. Without role-based training and visible leadership support, users recreate old spreadsheets alongside the new system. Identify key users in each department early and involve them in testing.
4. The stabilisation phase
Go-live is not the finish line. The first close, the first payroll and the first peak season will surface issues. Plan four to eight weeks of hypercare with clear ownership, and keep the core project team available during that period.
Summary
- Analyse and reduce custom code before you start
- Treat data quality as a workstream with business ownership
- Invest in role-based training and key users
- Budget for hypercare after go-live