# ERP implementation: how to do it without losing a year > A realistic account of what implementation involves, where projects go wrong, and how to sequence the work so the business keeps running. **URL:** https://cubeerp.co.uk/guides/erp-implementation-guide **Published:** 2026-07-30 | **Updated:** 2026-08-06 | **Reading time:** 13 min ERP implementations have a poor reputation, and it is partly deserved. The failures are rarely caused by the software being incapable. They are caused by data that was worse than anybody admitted, processes that were never actually agreed, and a business that did not have the people available to do its half of the work. This guide describes the sequence we use and the parts that consistently take longer than planned. It is written to be useful whether or not you end up choosing CubeERP. ## The five stages, and what each is really for - Discovery. Understanding how the business actually works, which is frequently different from how it is described. The output is a configuration plan and a list of decisions the business needs to make. - Configuration. Setting the system up around those decisions - structures, rules, documents, permissions. Mostly supplier-led, but every unresolved decision becomes a delay here. - Data migration. Extracting, cleaning and loading customers, suppliers, items, bills of materials, pricing and open transactions. Almost always the longest stage, and mostly your work. - Training and rollout. Training by role rather than by module, with a period of parallel running or a staged cutover. - Support and improvement. The first three months after go-live, when the real requirements finally surface because people are using it for actual work. ## Data migration is the project If you take one thing from this guide, make it this: the data is the project. Every implementation we have seen run late ran late because of data, and it was visible early to anybody willing to look. The typical state of an established business’s data is duplicate customer records, part numbers with inconsistent conventions, bills of materials that are partly right, supplier prices last reviewed years ago, and stock figures that have not been verified. None of that is unusual and none of it is a criticism. It is simply work that has to happen, and it cannot be outsourced entirely because only your people know which of two similar part numbers is the real one. > Start data cleansing the week you sign, not the week configuration finishes. It is the only part of the project that can be brought forward. ## Where projects actually go wrong - No internal owner with real authority, so decisions queue and the supplier waits. - Data cleansing started too late and underestimated by a wide margin. - Scope expanding quietly - "while we are at it" - until the original objective is a subplot. - Training delivered as a module tour weeks before go-live, so nobody remembers it when it matters. - Configuring around habits rather than requirements, which rebuilds the old system’s limitations inside the new one. - Going live on the busiest month of the year because the date was set before anybody checked. - Treating the shop floor as an afterthought, then being surprised when the shop floor does not adopt it. ## Phase it, but phase it sensibly Big-bang go-live is occasionally right and usually risky. Phasing reduces risk, but only if the phases are chosen around data dependencies rather than around organisational convenience. A sequence that works for most manufacturers and distributors is: stock and purchasing first, because everything downstream depends on inventory being right; then sales orders and despatch; then production; then costing and reporting once there is enough accumulated data for the numbers to mean something. Phasing by department - "sales first, then operations" - sounds tidy and tends to fail, because it splits processes that share data down the middle. ## Training that survives contact with go-live Train by role, not by module. A warehouse operative needs to be excellent at four transactions and does not need to know what a routing is. Training them on everything guarantees they retain nothing. Train close to go-live rather than early - knowledge decays quickly when it is not used - and plan a second round six to eight weeks afterwards, when people have real questions rather than theoretical ones. That second round is the single highest-value day in most implementations, and it is the one most often cut. ## Go-live, and the fortnight after 1. Freeze scope well before the date. Anything new goes on a post-go-live list, without exception. 2. Pick a quiet period. Not year end, not your peak season, not the week two key people are away. 3. Count stock properly immediately before cutover. Going live on stock figures you do not believe undermines confidence in the system permanently. 4. Have supplier support physically or immediately available for the first few days, not on a ticket queue. 5. Expect a productivity dip for one to three weeks and plan capacity around it rather than pretending it will not happen. 6. Hold a short daily review for the first fortnight to catch problems while they are still small. ## The three months afterwards The real requirements emerge after go-live, once people are using the system for real work rather than imagining how they might. Reports get requested that nobody thought of during discovery, and processes get refined because the data now shows something that was previously invisible. Budget time and money for this period. Projects that treat go-live as the finish line end up with a system that works exactly as specified and not quite as needed. ## Key takeaways - Data is the project - start cleansing the week you sign. - You need one internal owner with authority and protected time. - Phase around data dependencies, not around departments. - Train by role, close to go-live, and again six weeks after. - Count stock before cutover, and pick a quiet month. - Budget for the three months after go-live; that is when real requirements appear. ## Frequently asked questions **How long does an ERP implementation take?** For a mid-sized manufacturer, typically three to nine months depending on complexity and how clean the data is. Anybody quoting six weeks without seeing your data is guessing, and the guess will be wrong in one direction only. **How much of our time will it take?** Expect one person effectively full-time for the duration, plus meaningful input from finance, operations and the shop floor. If that is not available, delay rather than start understaffed. **Should we run the old system in parallel?** For finance, often yes for a period. For operations, rarely - running two operational systems doubles the work at the worst possible moment and usually means neither is maintained properly. **What do we do about historical data?** Migrate open transactions and enough history to be useful - typically two to three years of sales for reporting continuity. Archive the rest as read-only. Migrating everything is expensive and rarely used. **What if we discover mid-project that something does not fit?** Raise it immediately rather than working around it quietly. Configuration change during the project is far cheaper than a workaround that becomes permanent, and a good supplier would rather hear it early. ## Relevant solution pages - **ERP Software** - One system for quotes, orders, stock, production, purchasing and invoicing - built in the UK for growing businesses. https://cubeerp.co.uk/software/erp-software - **Business Management Software** - One place for customers, orders, stock, jobs, suppliers and invoices, so the business stops being run from a folder of spreadsheets. https://cubeerp.co.uk/software/business-management-software - **Stock Control Software** - Multi-location stock with bin locations, barcode scanning, batch and serial traceability, and figures that are right first time. https://cubeerp.co.uk/software/stock-control-software ## Related guides - **How to choose an ERP system: a practical checklist** - How to run a selection that produces a decision you can defend - the questions to ask, the demonstrations to insist on, and the answers that should worry you. https://cubeerp.co.uk/guides/how-to-choose-an-erp-system - **What an ERP system actually costs in the UK** - The pricing models, the costs that are not on the quote, and how to build a total figure you can take to a board without embarrassment. https://cubeerp.co.uk/guides/what-erp-costs-uk - **Signs you have outgrown spreadsheets and your accounts package** - How to tell the difference between a business that is busy and a business whose systems have stopped keeping up - and what to do about it. https://cubeerp.co.uk/guides/signs-you-have-outgrown-spreadsheets ## Contact - **Product:** CubeERP - **Trading name of:** Cube Systems Limited (company number 17220899, ICO registration number ZC216972) - **Email:** hello@cubeerp.co.uk - **Sales:** sales@cubeerp.co.uk - **Support:** support@cubeerp.co.uk - **Telephone:** 01234 672 617 (+441234672617) - **Address:** Unit 11, Olney Business Park, Osier Way, Olney, Buckinghamshire, MK46 5FP - **Opening hours:** Monday to Friday, 9am to 5.30pm - **Part of:** Crushed Ice Group (https://crushedicegroup.co.uk)