Excel VisualBasic Script

Sub HighlightFirstUnique()
    With Range("A1:A15")
        .Select
        .FormatConditions.Delete
        .FormatConditions.Add Type:=xlExpression, Formula1:="=COUNTIF(A$1:A1,A1)=1"
        .FormatConditions(1).Interior.Color = RGB(255, 0, 0)
    End With
End Sub