Validation

R

Richard

What am I doing wrong? Column A I've got =countif(a:a,2)=1 because I don't
want duplicate numbers entered. No matter what is entered even numbers that
aren't duplicates, I still get my warning message and won't allow me to enter
anything. Thanks in advance!!
 
G

Gord Dibben

Select column A and Format>CF>Formula is:

=COUNTIF(A:A,A1)=1

I would tend to use a more realistic range like =COUNTIF($A$1:$A$1000,A1)=1

but you know your needs.


Gord Dibben MS Excel MVP
 
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