Date Filter Dropdown - Some in Expandable Year->Month->Day format; others just mm/dd/yyyy

Hello All,

Having a strange problem with Excel. I have a table with a column of dates. When I click on the filter dropdown, some of the dates are grouped in this format (year and month is expandable):

2014
January
03
08
March
21
23

But then some other dates are just on the bottom like this:
01/26/2014
08/11/2013

Why is excel grouping some of the dates and not others? I have formatted the entire column as Short Date (doesn't fix it).

Windows 7 64x / Excel 2010

Thanks!!

Change format in columns D, H, I, J to General You will notice that some "dates" remain dates, other changed to numbers like 42 thousand+. The later are real dates and will be grouped into years, momyhs etc.
The first are just texts which only look like a date.

Once seen where is the problem, format back as desired date format, and change content from "date-like texts" into "real excel dates":
To change it you may use text to columns tool from Data ribbon and set datatype in given column as date with proper DMY sentence (so in your case MDY).

Glad it worked, and thanks for marking thread Solved, and for Reputation point