Data validation can't prevent a user from leaving a cell blank, or from
clearing a cell.

In the data validation dialog box, if you remove the check mark from
Ignore blank, users will be prevented from leaving the cell blank when
correcting an invalid entry.

Perhaps you could check the cell's contents in another formula on the
worksheet, and display a message if the cell is empty, e.g.:

=IF(A3="","Select Y or N in cell A3",B3*C3)

Tetsuya Oguma wrote:
Hi all,

I have got a Named range including two cells, including "Y" and "N" in each
cell. Then, I link that up with Data Validaiton List pointing to the Range.

This yet still allows users to enter blank cell and get away with it...

Q: How can I prevent users from entering blank?

Thanks in advance.

Tetsuya Oguma


--
Debra Dalgleish
Contextures
http://www.contextures.com/tiptech.html