Preventing duplicate data

[tillytee1]

Hello

Can anyone please help me?! I have found a formula that is meant to 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 want duplicate values entered anywhere in column A.

Eg - If I have entered 1234-10 in cell A7 and then try to enter the 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, Custom 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 duplicate even if it isn't already there.

PLEASE HELP ME!!!!!

Thanks
T

[Ardus Petus]

Works by me!

HTH
--
AP

"tillytee1" <[email protected]> a écrit
dans le message de
news:[email protected]...
>
> Hello
>
> Can anyone please help me?! I have found a formula that is meant to
> 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 want
> duplicate values entered anywhere in column A.
>
> Eg - If I have entered 1234-10 in cell A7 and then try to enter the
> 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, Custom
> 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 duplicate
> even if it isn't already there.
>
> PLEASE HELP ME!!!!!
>
> Thanks
> T
>
>
> --
> tillytee1
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> tillytee1's Profile:
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> View this thread: http://www.excelforum.com/showthread...hreadid=524300
>

[tillytee1]

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