Select the range for your list (p.e. A2:A100)
From Data menu, select Validation
Allow=Custom
Formula=(COUNTIF($A$2:$A$100;$A2)<2)
(this formula is for my example range of course - you have to use your own
range here)
You also can edit error messages for dubblicate entry here on Error Alert
tab.
Press OK when you are finished.
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.