Although if your intent is to delete the duplicates, you might cosider
putting the formula in an adjacent column, then use Autofilter to filter for
values 1 and deleting them.

Just be sure to back up your data (unless you intend to use the email
addresses for spam - then don't back up your data).



"JMB" wrote:

Let's say your data is in A1:A100. Select A1:A100 and click
Format/Conditional Formatting

Formula Is: =COUNTIF($A$1:$A1,$A1)1

then select whatever format you want. Modify as needed.


"FX 2000 Inc" wrote:

Does Excell have a built in feature that can find, alert or highlight
duplicate email addresses from of master email files?

If not, can anyone recommend a software program that can filter duplication
from an Excel file list?