ERP Data Migration: Moving from Excel or Legacy Software

By P-Soft Expert Team October 15, 2026 11 min read

ERP data migration means moving your master data (customers, suppliers, parts and product structures), opening stock, open orders and account balances from Excel or legacy software into the new system — after cleansing and consistent coding, with a short parallel-running period and a fixed cut-over date for switching off the old system. Rush it, and even the best ERP will produce wrong reports from day one; plan it, and the factory moves off the old system without stopping production.

This guide is written for factory managers, finance managers and project leads who want to know exactly what data migration involves, where to start and which mistakes cost the most. Whether your data is scattered across a dozen spreadsheets or locked inside an old program that no longer keeps up, the steps are largely the same.

What Data Should You Migrate to a New ERP?

The first decision is not to move everything. Split your data into three groups: information the new system cannot run without, information needed to continue current work, and records you only keep for reference.

Data group	Examples	Key point
Master data	Customers, suppliers, subcontractors, list of parts and materials, units of measure	Remove duplicates and standardise codes before anything else
Product structure (BOM)	Materials for each part, routing steps, semi-finished parts	Only for products you still make or sell
Opening stock	Quantity of each item in each warehouse on the start date	Based on a physical stock count, not book figures
Open orders	Undelivered sales orders, purchase orders not yet received, subcontracted work in progress	With their exact status on that day, not their original status
Balances	Receivables from customers, payables to suppliers, advance payments	Must be reconciled with your current accounting
Historical records	Closed orders and invoices from previous years	Usually not worth migrating in full; a searchable archive is enough

Moving years of closed transactions is tempting, but it multiplies the project’s workload and carries old errors into the new system. Most factories work perfectly well with customer history and recent orders, and keep the old files purely for reference.

Data Cleansing and Coding: The Most Important Step in ERP Data Migration

In most projects, cleaning the data takes longer than the transfer itself. The reason is simple: a spreadsheet lets everyone type whatever they like, while an ERP needs one shared language.

Typical problems in factory spreadsheets

One customer under several names, for example “Alpha Co.”, “Alpha Industries” and “Alpha Co. (Mr. Smith)”.
One part with two different codes — one in the warehouse, another in engineering.
Inconsistent units, such as sheet metal counted in kilograms in one file and in sheets in another.
Cells that mix numbers and notes, like “20 pcs – rest next week”.
Dates entered in different calendars or formats.

Write your coding rules before you start

Prepare a short document that defines how a part code is built, how individual and company customer names are written, and which base unit each item is counted in. Have engineering, the warehouse and finance sign it together, because all three will live with these codes afterwards. In a hypothetical example, a parts manufacturer could build its codes from “item group + subgroup + sequence number”, so that anyone can tell from the code what kind of part they are dealing with.

How to Migrate Excel to ERP: Step-by-Step Process

Inventory your data sources: list every file, ledger and system that holds information today, and assign an owner to each.
Map the fields: decide which new field each old column goes into, and which columns will be dropped.
Cleanse: fix or remove duplicates, incomplete codes and records no longer in use.
Trial load: load the data once into a test environment and review the result with each department.
Correct and repeat: fix the errors you find at the source, not only in the new system.
Final load: on cut-over day, the latest stock, open orders and balances are transferred.
Sign-off: each department confirms that its own data is correct.

Do not underestimate the trial load. Seeing your own real data in the new system’s forms reveals things no meeting ever will — a field that has always been empty, or a customer nobody can say is still active. If you have not yet settled the overall rollout plan, our ERP implementation guide gives the bigger picture of the project phases.

Parallel Running: Should Old and New Systems Run Side by Side?

Parallel running means recording key transactions in both systems for a short period and comparing the results. It builds confidence, but it has a cost: staff do every task twice, and the fatigue of double entry becomes a source of errors in its own right.

A middle path is to limit it: only in high-risk areas such as the warehouse and finance, and only for a short, pre-announced period. At the end, the key figures of both systems are compared; if no unexplained difference remains, the old system becomes read-only.

ERP Data Migration Checklist Before Go-Live

The number of active customers, suppliers and parts matches in both systems, or the difference is explained.
Total stock in each warehouse matches the signed stock-count record.
For a few fast-moving items, stock has been counted on the shelf at random and compared with the system.
Total receivables and payables match the current accounting trial balance.
Every open sales order shows the correct delivered and remaining quantities.
Engineering has checked several sample product structures line by line.
Users in each department have completed at least one real daily task with the migrated data.

Common ERP Data Migration Mistakes

Migrating “as is”

The biggest mistake is loading files without cleansing in the hope of “fixing it later”. Later rarely comes, and dirty data destroys users’ trust in the system within the first week.

Book stock instead of a physical count

If the stock figure is taken from the old system’s report, years of accumulated discrepancies move straight into the new one. A stock count before cut-over is a cost worth paying.

Data without an owner

When nobody is clearly responsible for the accuracy of the parts list or customer balances, errors get passed from department to department. Every data group needs a named owner.

Choosing the busiest period for cut-over

Going live at the peak of orders or during year-end closing doubles the pressure. If you are still unsure whether it is time to replace your current system at all, read when to replace your ERP.

Cut-Over Day: Planning the Switch to the New System

Cut-over is the moment the old system is closed to new transactions and all work moves to the new ERP. A hypothetical sample plan for a mid-sized factory could look like this:

A few days before: formally announce the date to all departments and key suppliers; stop creating new master data in the old system.
Last day on the old system: post the final receipts and issues, count stock and take a full backup.
Cut-over day: final transfer of stock, open orders and balances; a quick check against the validation checklist.
First working day on the new system: the project lead and one person from each department are on hand to clear small blockers.
First weeks: a short daily meeting to log and follow up issues; the old system stays open for reference only.

Data Migration into Data, the On-Premise Manufacturing ERP

With Data, P-Soft’s manufacturing ERP, migration is not left to the factory alone: P-Soft’s team moves your existing data — whether it sits in Excel or in previous software — into Data. The scope and level of this service is agreed in the contract, so it pays to bring a list of your data sources to the very first meeting.

Data is installed on the factory’s own server, so the data you have worked hard to clean never leaves your local network, and the system works without internet access. Users reach it through a browser on any PC or tablet. What you migrate has a clear home in the system: a customer database with full order history, suppliers and subcontractors, parts and item classification, and stock across multiple warehouses. In the Pro plan, materials and routing steps for each part are recorded too, and in the Elite plan a form builder lets you add your own custom fields to core forms such as customer, supplier and part — so the special columns in your old spreadsheet do not have to be thrown away. Warehouse history in Data cannot be altered, which makes an accurate opening stock even more important. The plans are Start, Pro and Elite, and the interface is in Persian.

Keep in mind that Data is not payroll, HR, time-and-attendance, tax or e-invoicing software, and it is not a cloud service; data for those areas stays in the specialised systems you already use. To see where Data fits in a factory, read about on-premise ERP installed on your own server.

Frequently Asked Questions

How long does ERP data migration usually take?

It depends on the volume and quality of your data. Most of the time goes into cleansing and coding, not the transfer itself; the tidier your files, the shorter the project.

Do we need to migrate years of historical records?

Usually not. Master data, stock, open orders and balances are essential; closed records can be archived and kept for reference.

Where should the opening stock come from?

From a physical stock count as close as possible to cut-over day, not from the old system’s report, so past discrepancies do not enter the new system.

Is parallel running of both systems necessary?

For high-risk areas like the warehouse and finance, a short, pre-announced period is useful; long parallel running mostly brings fatigue and errors.

Who migrates the data into Data?

P-Soft’s team transfers your previous data from Excel or earlier software into Data; the scope and level of this service is defined in the contract.

To review the state of your factory’s data and see Data working with realistic examples, explore Data manufacturing ERP and request a demo.