DUPLICATE_VALUE

A field marked Unique already holds the value on another record. The message includes the ID of the existing record.

Common causes

• An insert was used where an update or upsert was intended.
• The same value appears twice in one load file.
• A trigger or flow copies a value into a unique field.
• A job was re-run after a partial failure and tried to create the same records again.

How to fix

• Open the record ID from the message and decide whether to update it or merge.
• Use upsert with an external ID field so repeated loads update rather than insert.
• Remove duplicates from the source file before loading.
• If the field does not need to be unique, clear the Unique setting.