Event data import fails with duplicate lookup values in attendee records

CRM Microsoft Dynamics 365 Sales
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1

We’re migrating historical event data from our legacy system into Dynamics 365 Sales (9.0) and running into a blocker with attendee records. The Import Wizard fails when processing event registrations because multiple attendees share the same email address but map to different Contact IDs.

The error message shows:


Duplicate lookup reference detected
Contact: duplicate@company.com
Multiple target records found: 3

Our duplicate detection rules are active on the Contact entity, but they’re not catching these during import - only after the lookup resolution fails. We’ve tried using Power Query to pre-clean the data by removing duplicates based on email, but this causes us to lose legitimate attendee records for group registrations. The event scheduling is now blocked for 200+ upcoming events. How do others handle contact ID mapping when importing event data with potential duplicate lookup values?

2

Thanks for the suggestions. We tried merging duplicate contacts first, but our business requires keeping some duplicates separate (different departments, same email domain). The alternate key approach sounds promising - can you elaborate on how to set that up in the Import Wizard?