Preparing 1C data for migration: a 20-point checklist

The governing principle: move less than you want to

Short answer. You migrate master data, balances as of a cut-off date, and open documents. Not the full posting history.

The temptation to "move everything" is understandable but expensive: history inflates the scope, drags the old and new charts of accounts into a reconciliation exercise, and is almost never used afterwards. The legacy system stays available read-only for the statutory retention period, which is enough for audits and checks.

Decisions to make before any export

These are accounting decisions, not technical ones. Without them the export has nowhere to land.

1. Cut-off date. The start of a quarter or year works best. Balances are calculated as of it.
2. Chart of accounts. Build the new one and map it to the old. This is the longest part of preparation.
3. Dimension structure. Which two dimensions become global — a decision for years, covered in our article on dimensions.
4. Costing method. Set before the first entry and effectively permanent afterwards.
5. Document numbering. Continue the existing sequence or start a new series.
6. Parallel run period. How many weeks both systems run together and who owns the reconciliation.

Counterparties: the key structural difference

In 1C a counterparty is a single master list. In Business Central these are two separate entities: Customer and Vendor, each with its own card, terms and posting groups. A company you both buy from and sell to becomes two records.

What to do before the export:

7. Classify the list into customers, vendors and both.
8. Clean up duplicates. One counterparty entered three times with different spellings is normal for a five-year-old database. Match on the company registration number, not the name.
9. Verify tax details. Registration numbers, VAT status — everything that later drives tax documents.
10. Flag inactive records. Counterparties with no transactions in two years should not travel; they only clutter the master list.
11. Standardise names. One format for legal form, quotation marks and abbreviations.

Items

12. Units of measure. Business Central holds a base unit on the card and other units as conversion factors. Mixing pieces, packs and cases without factors is a classic cause of wrong balances after migration.
13. Duplicates and near-duplicates. One product under three codes will produce three different costs.
14. Categories and posting groups. Business Central distinguishes inventory posting groups (which drive accounts) from item categories (which drive navigation). These are different things and should not be conflated.
15. Dormant items. Zero balance and no movement in two years means it stays behind.

Balances and open documents

16. Inventory balances in quantity and value. Reconcile against the trial balance as of the cut-off date before the export, not after.
17. Open receivables and payables, document by document. Not as a single total per counterparty — otherwise you lose the ability to apply incoming payments to specific invoices automatically.
18. Open orders. Sales and purchase orders that still carry obligations.
19. Fixed assets. Acquisition cost, accumulated depreciation, method and useful life — a separate block, since it needs its own setup.
20. Currency balances and rates. The rate at the cut-off date and the mechanism for updating it afterwards.

How the data gets loaded

The built-in tool is Configuration Packages (RapidStart). The system exports an empty Excel template with the right columns for each table, you fill it with prepared data, load it back and review errors before applying.

Load order matters, because records reference each other:

1. foundation setup and reference data: currencies, units of measure, posting groups;
2. chart of accounts and dimensions;
3. customers, vendors, items;
4. balances and open documents through journals.

Every stage goes into a test company first. The rule that saves projects: no export is ever loaded into the production database on the first attempt.

How to know the migration worked

• Balances per account in Business Central equal the 1C trial balance as of the cut-off date.
• Inventory quantity and value match per location, not only in total.
• Open balances match document by document — spot-check the ten largest counterparties.
• The count of active customer and vendor cards matches what you expected after de-duplication.
• A test payment applies to the intended document automatically.

The migration process itself is described on our 1C migration page, and you can size the work in the cost calculator.

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