Errors
Parse
Unreadable files show a local error and stay on upload. Since 0.1.12, a Hosted config load failure with no local fields stays on Retry and does not open an empty upload step. When local fields are passed, those fields stay available.
Validation
Invalid cells mark the preview and list a message under the cell. Counts include all rows; the table shows the first 100.

Import button
Disabled when there are zero valid rows, and after a successful Import click until the user goes back to mapping. If onComplete throws or rejects, Import re-enables and the widget shows the error. Clicking import sends only valid rows to onComplete.
Related: Error export · Validation · Handle invalid CSV rows