We Migrated CRMs and Got 40,000 Duplicate Contacts

Six months ago we migrated from HubSpot to Salesforce. The migration itself went fine. Data mapped correctly, custom fields transferred, nothing broke. We celebrated for about three days. Then our sales team started complaining. "Why do i have two records for the same company?" "Why is this contact listed three times?" "I just called someone and they said another rep already reached out this morning." We pulled a report. 40,000 duplicate contacts. Out of roughly 95,000 total records. More than 40% of our database was duplicates. And the thing is, most of those duplicates already existed in HubSpot. We just hadnt noticed because HubSpot's dedup was handling some of it silently. When we moved to Salesforce, all the silent duplicates became visible and the mess that had been building for three years landed on our desk at once. Why CRM migrations create duplicate nightmares The duplicate problem in CRM migrations comes from multiple sources and they compound in ways that are hard to predic