How much historical data should you migrate to a new ERP?
Migrate opening balances, every open transaction and enough summarized monthly history to run the comparative reports you need, often the current and prior fiscal year. Bring full transaction detail only where users drill into it regularly. Whatever stays behind in the old ERP still needs a retention decision and a value decision before the system is switched off.
The short answer: balances, open items and enough summarized history
Migrate opening balances, every open transaction and summarized monthly balances for as many prior periods as your comparative reports need, which for many companies means the current and prior fiscal year. Move full transaction detail only for data people will drill into regularly. The rest stays in the old system or an export, and it still needs a decision about retention and value.
That answer holds whether the move is QuickBooks to Sage Intacct, a legacy on-premises package to NetSuite, or one cloud ERP to another. What changes is how much each extra year of detail costs to map, cleanse and validate.
What are the options for migrating ERP history?
| Migration depth | What moves | Effort and risk | When it fits |
|---|---|---|---|
| Opening balances only | Trial balance at cutover by account and dimension | Lowest; quick to validate | Simple businesses with clean books and little need for comparatives |
| Balances plus open items | Trial balance, open AR and AP, open purchase and sales orders, inventory on hand, fixed asset register | Low to moderate; open items must reconcile to control accounts | The practical minimum for an operating company |
| Summarized history | Monthly balances by account, department or class for prior periods | Moderate; mapping an old chart of accounts is the hard part | Comparative reporting, budget versus prior year, trend dashboards |
| Full transactional detail | Every journal line, invoice, receipt and payment for selected years | Highest; master data cleanup and volume testing multiply | Teams that open prior-year transactions inside the ERP every week |
A rule worth writing into the scoping document: migrate what people report on; archive what people only look up. If a controller opens a 2019 invoice twice a year, an archive lookup is far cheaper than migrating every 2019 invoice.
Which five questions settle the scope?
- Which reports need comparatives on day one? Board packs, lender covenant reports and budget-versus-prior-year views set the minimum years of summarized history.
- Who drills into old transactions, and how often? Weekly lookups argue for migrating detail; occasional ones argue for an archive.
- What will auditors and tax advisers need, and for how long? Their guidance sets how long old data must stay retrievable, which is not the same as where it must live.
- How clean is the old master data? Duplicate vendors, retired items and obsolete account codes make every migrated year more expensive.
- What happens to the old system after go-live? If its license ends three months after cutover, the archive plan is part of the migration plan, not an afterthought.
What happens to the history you leave behind?
Every year of detail you do not migrate still exists, and someone has to decide its fate. The guide to legacy ERP data archiving options after a migration compares keeping it live, a read-only archive, exporting it and deleting it.
| Left-behind data | Retention question | Value question |
|---|---|---|
| GL and subledger detail for prior years | How long must it stay retrievable for tax and audit? | Does it show how the business ran over time? |
| Purchase orders, approvals and match exceptions | Are any items under dispute or legal hold? | Does it record decisions and their outcomes? |
| Customer and vendor master history | Does it contain personal data with retention limits? | Does it link to CRM and support records? |
| Attachments: scanned invoices, contracts, notes | Where will they still be readable in five years? | Do they explain why transactions happened? |
| Custom reports and scripts | Does anyone still rely on them? | Do they document how the company measured itself? |
For Sage users, see what Sage 100 and Sage 300 hold before a cloud move.
Can the history you don't migrate have value?
Sometimes. Detailed ERP history, meaning approvals, exceptions, credit holds and variance notes linked to email, CRM and support records, is a record of real work, and that is what AI developers need to train and test agents that carry out business tasks. A company can license that kind of record through SourceX, keeping ownership and receiving a one-time payment if a deal closes. Depth, connection between systems and clear rights drive value far more than the ERP brand; the explainer on how much company data is worth sets out the factors.
It is only worth raising for established clients: US-based, 50+ full-time employees at peak (contractors excluded), a multi-year operating history, records the company has the right to license, and an executive prepared to sponsor the process.
What does this mean for ERP consultants?
You see the client's full history at the exact moment it is about to be left behind, so the cutover plan is the natural place to raise the question. One line in the archive section is enough: "Before decommissioning, confirm whether the retained history has licensing value." If the CFO is interested, you make the introduction and step back; your role ends there, and the records stay with the client and its team.
Finance teams in the middle of a go-live will worry about workload, and the answer to our finance team has no bandwidth for a data licensing project addresses that directly. The ERP consultant partner page explains how implementation firms work with the program.
Partners earn 25% of the eligible platform fees SourceX actually collects from the referred company's licensing deals, capped at $100,000 per referred company, paid only after the buyer pays and SourceX receives its fee.
What are the limits of this answer?
- Regulated industries can have record-keeping rules that override the general pattern; confirm with the client's counsel.
- Retention periods vary by record type and jurisdiction; take them from the client's tax adviser.
- Some ERPs restrict how history can be loaded or reported; check the target vendor's documentation rather than assuming.
- A company that deletes the old instance without an export loses both its audit trail and any licensing option.
Next step
Add the archive and value decision to your next cutover plan, and run borderline clients through the company fit checker. To be credited for introductions, register as a partner.
- Step 1Share your linkSend your personal link to a company you know.
- Step 2Company appliesThe company applies itself at /apply.
- Step 3Buyer selects and paysThe buyer selects and pays for the data and SourceX receives its fee.
- Step 4You get your rewardYour share of SourceX fees becomes payable.
Common questions
How many years of history should we migrate to a new ERP?
Enough summarized history to run the comparative reports you need on day one, which for many companies means the current and prior fiscal year at monthly level. Full transaction detail beyond open items is worth migrating only when users look it up often. Older years can stay in an archive or export that auditors and analysts can still search.
Should we migrate closed transactions or just balances?
Balances plus open transactions cover what the new system needs to operate: open invoices, bills, orders and inventory must reconcile to control accounts on day one. Closed transactions add history, not function. Migrate them only where people need them inside the new system, and keep the rest retrievable in an archive to avoid the cost of mapping and validating them.
Can more history be migrated after go-live?
Often, as a second phase once the new chart of accounts and master data have settled, although each extra load needs its own mapping and validation. Phasing lowers cutover risk. It only works if the old data is still accessible, so keep the legacy system or a complete export available until the phase is finished or formally dropped.
Who decides how much history to migrate, the consultant or the client?
The client decides, typically the CFO or controller with input from auditors and the people who build reports. The consultant lays out the options, the effort and risk of each, and what happens to the data that stays behind. Record the decision in the scoping document so nobody reopens it in the middle of testing.
Does leaving history in the old ERP create any risk?
Yes, if nobody owns it. Access can lapse when the old license ends, the people who understand the old system leave, and personal data in old master files can outlive its retention period. Assign an owner, set a retention and review date, and make sure a complete, documented export exists before the old system is switched off.
Related pages
- Legacy ERP data archiving: keep it live, archive it read-only, export it or delete it?
- Sage 100 and Sage 300: legacy accounting history before a cloud move
- How much is company data worth?
- Our finance team has no bandwidth: how much time does data licensing take?
- Referral opportunities for ERP consultants
- Check Company Fit for Data Licensing
Free resources
- MOIC calculator — Multiple on invested capital from realized and unrealized value.
- PDF bank statement to CSV converter — Turn Chase, Bank of America or Wells Fargo PDF statements into CSV, privately in your browser.
- Client data licensing eligibility checker — A transparent preliminary screen for one company.
- All free tools · MCP resource center
By SourceX Partnerships Team · Published 2026-10-09 · Updated 2026-10-09
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