Filtering Values not showing all data

Hi,

My workbook contains a column (A) that has dates in it(65000 ish total rows), which are every Saturday from January 2015 to present (130 or so unique values).
Up until a week ago, the filtering of this column allowed me to filter by Year->Month->Day/week.

Now for some reason it will not let me filter past May30th 2015.
That date happens to be around line 10000.
For trouble shooting purposes I deleted all of may 30th 2015 data, and it will then show me the following June 6th data, which again stops the data in the filtering values list around row 10000...

And to add to the mess that this is becoming. The filtering will work on some users computers but not on others...

Hard to explain, but is there some limitation in Excel that is stopping the filters from looking past row 10000? Or a user setting that can be adjusted?
There are no blank rows.
I've pasted just that column into another workbook and the same issue occurs.

Can someone please enlighten me?

I tried to add the file as an attachment to this post, but it is not working for me. I can send via email if you are willing to help.

Thanks in advance;