STRING_TOO_LONG Error When Running a Salesforce Flow

Cause 1: Field Default Value Exceeds Field Size Limit

If any field on the affected object contains a default value that exceeds the field's character size limit, the Flow UPSERT will fail. Note the following:

• Affected fields may or may not be referenced in the Flow directly — even fields that exist on the object but are not part of the Flow can trigger this error if their default value is too long.
• Soft-deleted fields (fields that have been deleted but still exist in the schema) are also counted.
• Salesforce counts all underlying special characters, line breaks, and hidden formatting characters toward the total character limit of the field, pushing the total length over the limit even when the visible text appears short.
  
  

Cause 2: Value Mapped in Flow Record Create Exceeds Field Size Limit

During a Record Create step in the Flow, if a value is explicitly mapped to a field and that value's character length exceeds the field's defined size, the UPSERT operation fails.

Resolution

To resolve this, either correct the limits or remove the fields completely.