Errors

Parse

Unreadable files show a local error and stay on upload. Hosted config load failures surface an alert and still show the upload step (local fields remain available when passed).

Validation

Invalid cells mark the preview and list a message under the cell. Counts include all rows; the table shows the first 100.

Preview table with invalid email, number, enum, date, and a duplicate of row 1.

Import button

Disabled when there are zero valid rows, and after an Import click until the user goes back to mapping. Clicking import sends only valid rows to onComplete.