Excel cannot recognize canonical date format. If the date format in the XML data is in canonical format, that is, YYYY-MM-DDThh:mm:ss+HH:MM, you must apply a function to display it properly.
One option to display a date is to use the Excel REPLACE and SUBSTITUTE functions. This option retains the full date and timestamp. If you only require the date portion in the data (YYY-MM-DD), then another option is to use the DATEVALUE function. The following example shows how to use both options.
Example: Formatting a Canonical Date in Excel
Using the Employee by Department template and data from the first example, this procedure adds the HIRE_DATE element to the layout and displays the date as shown in Column E of the following figure: