Surfer 11 and previous versions did not have the ability to read different date formats. In these cases, you may be able to convert your date to a numeric value corresponding to the date format in Excel. If the date is in any format in cell B1, add a formula to cell C1 to convert the number to text, then convert the text to a value.
Please consult your Excel documentation for more information about functions in Excel.
Updated February 10, 2017