CRM & Accounts Data Migration: A Checklist for Switching Systems Safely

CRM Lab · 10 November 2026 · 7 min read

Data migration is where system changes succeed or fail. A practical checklist covering audit, clean-up, mapping, test runs, parallel running and sign-off.

Whether you're leaving Salesforce, HubSpot, Sage, QuickBooks or a collection of spreadsheets, data migration is where projects succeed or fail. Done well, your team switches over and everything is simply there. Done badly, you lose history, duplicate customers and trust in the new system. Use this checklist.

1. Audit what you have

• List every source: CRM, accounts, spreadsheets, shared inboxes, documents.
• For each, note record types (contacts, companies, deals, products, invoices, jobs) and roughly how many.
• Decide what history you really need: all of it, or the last few years plus open items.

2. Clean before you move

• Merge duplicates (the same company entered three ways).
• Standardise formats: phone numbers, postcodes, dates, VAT numbers.
• Archive dead records rather than migrating them.
• Agree who owns each clean-up task. Usually it's the people who use the data daily.

3. Map old fields to new

Create a simple mapping sheet: old field → new field → transformation rule. This is also the moment to drop fields nobody uses.

4. Do a test migration

• Migrate a sample (or everything) into a test copy of the new system.
• Have real users check records they know well.
• Reconcile totals: number of customers, open deals, outstanding invoice values.

5. Plan the cut-over

• Pick a quiet period (not month-end or VAT quarter).
• Freeze changes in the old system for the final export.
• Run a final migration and repeat the reconciliation checks.

6. Run in parallel, briefly

Keep the old system read-only for a few weeks so people can check anything that looks wrong. Then archive the export somewhere safe.

7. Don't forget compliance

• Keep accounting records for the period HMRC requires (generally six years).
• Apply your data retention rules under UK GDPR: don't migrate personal data you no longer have a reason to keep.
• Update your privacy notice if new suppliers process the data.

Common pitfalls

• Migrating duplicates and junk "to sort out later" (it never happens).
• Losing attachments, notes or email history that weren't in the main export.
• Breaking links between records, like deals that lose their company or invoices that lose their customer.
• Skipping user testing because the numbers "look right".

Migration is included in every CRM Lab build. See how we handle it for Salesforce, HubSpot, Sage and QuickBooks.