[Yandex DataLens] Data preparation not finished

ERR.DS_API.DB.MATERIALIZATION_NOT_FINISHED

Data preparation is not complete yet; wait a few more minutes or reload the data.

You get this error if file upload is not yet fully processed in the file, Google Sheets, or Yandex Documents connection.

The error also occurs when importing workbooks with such connections. To fix the error, reload the data after importing the workbook.