Guide
CRM migration without losing data
A step-by-step plan to move from spreadsheets or an old CRM to a new one: inventory, cleaning, mapping, test imports, cut-over and the checks that prevent lost history.
VAULT 33|27 · Updated 12 November 2026 · Reviewed 12 November 2026 · 2 min read
Step 1: inventory everything
List every place client data lives: the old CRM, spreadsheets, email contacts, accounting software, booking tools, phones. Note what each contains and who owns it.
Step 2: decide what moves
| Data | Usually move? |
|---|---|
| Active clients and contacts | Yes |
| Open deals, quotes and bookings | Yes, with their stage and value |
| Won deal history | Yes, at least totals, dates and services |
| Notes and key emails | Yes for active clients; summarise older ones |
| Files and documents | Link or attach for active clients |
| Contacts with no activity for years and no legal reason to keep | No; delete in line with your retention policy |
Moving is a good moment to apply data protection rules: keep only what you need and have a reason to keep.
Step 3: clean before you move
- Remove duplicates.
- Standardise phone numbers with country codes, names and company names.
- Fill in missing source data where you can.
- Fix obviously wrong emails.
Step 4: map the fields
| Old field | New field | Notes |
|---|---|---|
| Customer name | First name, last name | Split if needed |
| Phone | Phone (+44 format) | Standardise |
| Status | Pipeline stage | Map old statuses to new stages |
| Source | Lead source | Create the list first |
Step 5: test import
Import a sample of around 50 records. Check every field landed in the right place, that relationships (contact to company, contact to deal) survived, and that automations did not fire on imported records.
Step 6: cut-over
- Pick a quiet day and announce a short freeze on the old system.
- Export the final data and import it.
- Switch every enquiry channel to the new CRM.
- Keep the old system read-only for a defined period, then archive it.
Step 7: verify
- Record counts match, by type.
- Spot-check 20 active clients end to end.
- Test a new enquiry from every channel.
- Confirm reports show sensible numbers.
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