I want to update a number of Cases using a CSV file that contains two fields: case number (NOT technical id, but the automatically generated human readable id/name) and a textual complaint.
Data loader is not able to handle this and I found a suggestion to use Workbench instead. So I uploaded the file and set the proper fields. This is right before you start the actual upsert:
But when I click "Confirm Upsert", all records are rejected: "CaseNumber Not Specified, MISSING_ARGUMENT"
If I preview the CSV file, CaseNumber is filled with the data that I expect to see there.
What am I missing here?