Moving from Sage to NetSuite: A Migration Checklist for Irish Companies
What to move, what to leave behind, and how to reconcile balances so finance trusts NetSuite from the first month-end. A practical checklist.
Eirvancee · 12 November 2026 · 7 min read
Most companies arrive at NetSuite from Sage, Xero or QuickBooks, usually with a few spreadsheets doing the jobs the accounts package never could. The software change gets the attention. The data migration decides whether finance trusts the new system in its first month.
This checklist sets out how we approach it, in the order it should happen.
1. Decide what moves and what stays behind
Not everything in the old system belongs in NetSuite. Agree three categories early.
- Master data: customers, suppliers, items, the chart of accounts, price levels, employees. This moves, after cleaning.
- Open transactions: unpaid customer invoices, unpaid supplier bills, open sales and purchase orders, stock on hand. This moves, line by line.
- History: closed invoices and old orders. Usually summarised by month for comparison reporting, with the detail kept in the old system or an archive.
Moving full history sounds safer but rarely is. It multiplies the work of reconciliation and carries old mistakes into a clean system.
2. Clean the data before you move it
Every legacy system holds duplicates, dormant accounts and inconsistent naming. Migration is the one moment when cleaning it is cheap.
- Merge duplicate customers and suppliers, and agree which record survives.
- Retire items that have not sold or been bought for a set period.
- Standardise units of measure, item naming and address formats.
- Check VAT registration numbers and tax treatment on every customer and supplier, including EU and UK accounts.
The people who own each list should sign it off. Finance owns the chart of accounts. Operations owns items. Sales owns customers.
3. Redesign the chart of accounts, carefully
Many Sage charts of accounts have grown codes to do jobs that NetSuite handles with departments, classes and locations. A sales account per branch, for example, becomes one sales account with a location field.
Map every old code to its new home and keep the mapping as a document. Your auditors will ask for it, and it is how opening balances are traced from one system to the other.
4. Build the load templates once, and reuse them
Each record type gets a load template: the columns NetSuite expects, the mapping from the old fields, and the rules for transforming them. Building these properly takes time the first round, and saves it every round after.
Keep the templates under version control, or at least in a shared folder with dates, so each trial run uses a known version.
5. Run trial migrations and reconcile every one
A trial migration loads everything into a sandbox account exactly as the final cut-over will. Then finance reconciles it against the old system.
- Customer and supplier counts match.
- Debtors and creditors balances match, in total and by account.
- Stock quantities and stock value match, by location.
- The trial balance in NetSuite matches the old system at the cut-over date.
Every difference gets an explanation and a fix. Plan for at least two full trial runs, and more if the first reveals serious data problems. When a trial run reconciles to zero with no manual adjustments, you are ready.
6. Plan the cut-over weekend
The final migration is a rehearsed routine, not an event. Agree in advance:
- The last day transactions are entered in the old system.
- The order in which records are loaded, and who checks each one.
- How orders and payments that arrive during the cut-over are captured.
- The sign-off point at which NetSuite becomes the system of record.
Going live at the start of a financial period keeps opening balances clean and gives you a complete first month-end in NetSuite.
7. Support the first month-end closely
The first close in a new system always surfaces questions: a report that does not match the old one, a journal nobody knew was posted by hand, a VAT figure that needs explaining. Have the people who built the system available to the finance team for that first close. It is where confidence is won or lost.
The short version
Move less than you think, clean it before you move it, reconcile every trial run, and support the first close in person. A migration done this way is unremarkable, which is exactly the point.
If you are planning a move to NetSuite and want a second view on your migration plan, book a free 20-minute consultation with one of our consultants.