You've selected the 'Replace entire table data' option. This means that you're about to delete your entire table data and current column settings and replace it with data from your source file with default settings for columns.

If you have any date type columns in your file, please make sure you set the date input format in Main settings of plugin to the one you're using in your source file first.

Please consider duplicating your table first, before updating.

There is no undo.