right click sheet tabview codeinsert thismodify for your columnSAVE

Private Sub Worksheet_Change(ByVal Target As Range)
If Target.Column < 2 Then Exit Sub
If Application.CountIf(Columns(2), Target) 1 Then MsgBox "Dup"
End Sub


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Don Guillett
SalesAid Software

"waldo" wrote in message
...
I am entering numbers in a column and it is important that I get alerted to
any duplication of a previous number. How do I do this?