Go back to one of the validated cells and, from the menu bar, select Data
Validation. Click on the Error Alert tab. What selections have you made
there? Unless the first checkbox is selected, there won't be any
notification.

"Jon5001" wrote:

I've applied data validation (list setting) to some cells in my workbook. The
source is a named range in another sheet. When I click on the cells with
validation, the dropdown list with the values I expect appears and I can
choose them as normal. However, I can also type in any other value I choose
and excel will not complain. Anyone know what's causing this?