Preventing duplicate data

[tillytee1]

Hello

Can anyone please help me?! I have found a formula that is meant t
prevent duplicate data entry, but it doesn't seem to work properly!

I have a large spreadsheet with values in column A. I don't wan
duplicate values entered anywhere in column A.

Eg - If I have entered 1234-10 in cell A7 and then try to enter th
same value in cell A67, I want to be told that it is a duplicate.

I thought I found a solution which was using Data, Validation, Custo
and the formula -
=COUNTIF($A$6:$A$3000,A6)=1

BTW - My spreadsheet goes up to row 3000!!

However, this is now telling me that EVERY value I enter is a duplicat
even if it isn't already there.

PLEASE HELP ME!!!!!

Thanks
T:confused

 

[Ardus Petus]

Works by me!

HTH
--
AP

"tillytee1" <[email protected]> a écrit
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[tillytee1]

It's still not working for me...does anyone know what I'm doin
wrong?!!?
Thanks