Select your range which in my case is A1 - A40 and then
Data|Validation|Custom
enter the formula
=COUNTIF($A$1:$A$40,A1)=1
Mike
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments. After that, you can post your question and our members will help you out.