У вашего броузера проблема в совместимости с HTML5
In Excel, dates must be stored in a format that Excel understands otherwise Excel treats them as text (i.e. non-date) values. This video shows how to convert these "non-dates" to real dates which will then allow you to sort, filter and calculate.
This is a free lesson from my video-based training course "Excel - More Than a Numbers Game" in which you'll learn some simple-but-effective ways to save time when working with lists and text in general.
For more information see this page: http://theexceltrainer.co.uk/video-training-excel-more-than-a-numbers-game