KB183815 - Custom Date Appears or Date Is Missing in AutoFilter List

SYMPTOMS

The AutoFilter list contains one entry that represents two different dates. When you select the entry, both dates appear in the filtered list. -and-

When you click an item in the AutoFilter list, the selected item may be "(Custom...)" even though you have not previously selected the Custom item.

CAUSE

You are using the AutoFilter to filter a list that contains dates. -and-

The dates have been formatted to use only two digits for years. For example, January 1, 1925 appears as "1/1/25". -and-

The list contains dates in more than one century: for example, dates in the 20th and 21st centuries.

MORE INFORMATION

To see an example of the problem that is described in this article, follow these steps:

In Microsoft Excel, create a new workbook. In Sheet1, enter the following values and formulas:

      A1: Date       B1: Year
      A2: 1/1/1925   B2: =YEAR(A2)
      A3: 1/1/2025   B3: =YEAR(A3)
      A4: 7/5/1998   B4: =YEAR(A4)

Select cell A1. On the Data menu, point to Filter, and then click AutoFilter.
Click the arrow in cell A1.

Note that the list contains the following items:
(All)
(Top 10...)
(Custom...)
1/1/25
7/5/98
Select 1/1/25.

Note that both the 1/1/1925 and 1/1/2025 dates appear in the filtered list.
Click the arrow in cell A1.

If you are using Microsoft Excel 97, note that the "(Custom...)" item is selected in the list even though you have not previously selected it.
Click 7/5/98. Then, click the arrow again.

Note that the 7/5/98 item is selected in the list.
Click "(All)".
Select cells A2:A4. On the Format menu, click Cells. Click the Number tab. In the Category list, click Custom. In the Type box, type m/d/yyyy. Click OK.
Click the arrow in cell A1.

The dates each appear separately in the list. When you select a date, only that date appears in the filtered list.