A CRM migration is a change in how a business represents its customers. Moving rows successfully is only one part of the job. You also need to preserve ownership, relationships, dates, and the meaning of statuses. A clean import that assigns every opportunity to the wrong company is still a failed migration.
In this guide
Inventory before exporting
List the source systems, record types, approximate volumes, attachments, activity history, custom fields, and integrations. Identify which information is active, which must be retained for a documented reason, and which can be excluded. Assign an owner to resolve ambiguous data rather than leaving every exception to the technical team.
Take a protected, dated export and record how it was produced. Do not distribute a complete customer database through ordinary group email. Give access only to the people working on the migration and agree on how temporary copies will be removed.
Build a mapping workbook
For each source field, specify the destination, transformation, default behavior, and validation rule. A blank date should not silently become today's date. A missing currency should not inherit an arbitrary default. Map statuses by meaning, not just by matching similar words.
Keep the source record identifier in the destination where possible. It helps reconcile results, investigate problems, and prevent repeated imports from creating new copies. Import parent records before dependent records when the destination requires their identifiers to establish relationships.
Test a deliberately difficult sample
Use a sample containing ordinary records and edge cases: non-English names, long notes, multiple contacts per company, closed opportunities, blank fields, multiple currencies, and attachments. Confirm that character encoding, time zones, and line breaks survive.
Check relationships manually. Open a company and verify its contacts and opportunities. Open a contact and inspect its activity history. Do not rely only on the importer reporting “completed.” That message describes processing, not business correctness.
Reconcile more than totals
Compare record counts by type and status. Compare monetary totals by currency rather than adding unlike currencies. Sample owner assignments, date ranges, mandatory-field completion, and relationship links. Explain every discrepancy in a reconciliation log.
For example, if 500 source contacts become 470 destination contacts, the difference may be 30 approved merges or 30 lost records. Counts alone cannot tell you which. Retain the decisions and identifiers needed to demonstrate the outcome.
Plan the cutover and recovery
Specify when the old system stops accepting updates, who runs the final transfer, who verifies it, and who can authorize reopening work. Pause outbound automation so imported history does not trigger welcome emails or sales sequences accidentally.
Define rollback conditions before launch: broken associations, missing critical history, or failed access controls may justify stopping. Recovery must address new work created after cutover, not merely restore an older backup and lose fresh customer interactions.
Keep the old system available in an appropriate read-only state for an agreed transition period. Once users can complete their normal tasks and reconciliation is accepted, document the new authoritative system and retire temporary migration access.
Create a reconciliation worksheet
Give every imported record a source identifier, destination identifier, record type, migration status, and exception reason. For records intentionally merged or excluded, record the decision and its owner. This worksheet becomes the bridge between the old and new systems when someone asks where a particular customer went.
Compare totals at useful levels. For example, reconcile open opportunities by stage and currency, contacts by owning team, and attachments by linked record. A matching grand total can conceal an error in which one group is missing and another has been duplicated. Inspect both the count and the relationship structure.
A fictional cutover schedule
On the day before migration, the team reviews unresolved mapping exceptions and confirms who will be available. At the agreed cutover time, users stop editing the source system. The migration owner takes the final export, imports the data in dependency order, and runs the reconciliation checks. Business owners then validate a sample of their own records.
Only after acceptance should ordinary users resume work in the destination. If a critical check fails, pause and use the documented recovery decision. Do not allow half the team to work in the new system while the other half continues editing the old one without a deliberate synchronization plan.
Handle activity history realistically
Some systems export structured calls, emails, tasks, and notes differently. Decide which history must remain directly usable and which can be retained in a linked archive. Test whether timestamps, senders, recipients, and record associations retain their meaning. A single pasted block of text may preserve words while losing the context users need.
Check attachments separately. An export containing a file URL may not contain the file itself, and that URL may stop working after the source account is closed. Verify access from the destination before retiring the old service. Record exceptions honestly rather than marking a migration complete because the main contact table arrived.
Close migration access after acceptance
Remove temporary credentials, shared export links, and unnecessary copies once the agreed retention and recovery plan permits. Transfer ownership of routine administration to the ongoing team. Preserve the mapping, reconciliation log, and known limitations in an accessible project record.
Schedule a follow-up review after users have completed normal work in the new system. Look for missing associations, recreated duplicates, and automation that behaves differently with migrated records. The migration is operationally successful when users can trust the customer history and continue work, not merely when an import progress bar reaches its end.