An AutoFilter dropdown list will only show 1000 entries. If your column
has more than 1000 unique items, they can be filtered, but they can't
all be displayed in the dropdown list.


To AutoFilter for an item that doesn't appear in the dropdown list, you
can choose Custom from the dropdown list, and type the criteria. Also,
there are a couple of workarounds here:


http://www.contextures.com/xlautofilter02.html#Limits


Stealy Dan 1 wrote:
> I have frequently used the Auto Filter feature with my spreadsheets.
> Recently I clicked the down arrow to set the criteria I wanted to use for the
> filter, but the data (a name) was not on the list for me to select. Any
> ideas why, or what I should try?


--
Debra Dalgleish
Excel FAQ, Tips & Book List
http://www.contextures.com/tiptech.html