Choose the cutover date
Agree a date with your accountant. Complete the old records up to that date and use a reconciled trial balance as the starting point. Keep a copy of the original files.
Prepare the master records
Clean duplicate customer and supplier names. Review the chart of accounts and decide which physical locations and reporting tags you need. Check that dates, currencies and identifiers use a consistent format.
Separate opening balances from new transactions
Opening receivables and payables should preserve the unpaid documents needed for later settlement. They should not create current-period sales or expenses a second time. Stock opening quantities also need an agreed valuation basis.
Preview, reconcile, then commit
Use supported import templates and inspect validation results before committing an import. Compare trial balance totals, outstanding customer and supplier balances, and cash accounts against the old system. Keep both systems available until the checks are complete.
Examples are illustrative, not tax or legal advice. Your accounting policies and local requirements may change the treatment.