Diagnostics
Symptom
(ICM19000) DUPLICATE_VALUE:duplicate value found: Duplicate_Check__c duplicates value on record with id: a0F3N000000aIGY:--
Problem
The user receives the error message above when a DataMigrator flow writes to a Salesforce target.
Solution
The flow is performing an insert into an existing target where data may already exist. An UPSERT operation is necessary.
To select the UPSERT functionality, it is necessary to turn on OPTIMIZE LOAD in the flow. This is done by selecting the target properties and clicking on any white space in the flow screen to bring up the flow properties. Then you can select optimize load.