If you want to prevent duplicate Stock Numbers from being entered,
here's a thought . . .

If Stock Numbers are to be entered in Col_A, beginning in A2:
•Select A2
•DataData Validation
-Allow: Custom
-Formula: =COUNTIF(A$2:A2,A2)=1
•Set the error message to something like "Duplicates not allowed"
•Click OK
•Copy Cell A2 down as far as you need

That will test each Stock Number when it is entered and prevent
duplicates.

Note: It will not catch a duplicate if it is copy/pasted from another
cell.

Is that something you can work with?

Regards,
Ron


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Ron Coderre
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