how do i set up if cell content repeat, warn given

[Dave Peterson]

You mean like duplicate entries in a column?

You may want to look at Chip Pearson's site. He has lots of techniques to work
with duplicates:
http://www.cpearson.com/excel/Duplicates.aspx

lahiripranab wrote:

 

[Fred Smith]

Typically, you use Countif. If data is entered in a1, and you don't want it
to be a duplicate of anything in column B, use:

=if(countif(b:b,a1)>0,"Duplicate","OK")

Regards,
Fred.