Sub FillNewToYellow()

    Dim dic

    Dim oldArr(), updatedArr()

    On Error Resume Next

    If Worksheets("old") Is Nothing Then

        MsgBox "Missing old sheet"

    ElseIf Worksheets("updated") Is Nothing Then

        MsgBox "Missing updated sheet"

    Else

        Set dic = CreateObject("Scripting.Dictionary")

        ActiveWorkbook.Sheets("old").Activate

        oldArr = Range("B1:B" & ActiveSheet.UsedRange.Rows.Count)

        For i = 1 To UBound(oldArr)

            dic(oldArr(i, 1)) = ""

        Next

        ActiveWorkbook.Sheets("updated").Activate

        updatedArr = Range("B1:B" & ActiveSheet.UsedRange.Rows.Count)

        For i = 1 To UBound(updatedArr)

            If dic.exists(updatedArr(i, 1)) = False Then

                Rows(i & ":" & i).Select

                With Selection.Interior

                    .Pattern = xlSolid

                    .PatternColorIndex = xlAutomatic

                    .Color = 65535 'Yellow

                    .TintAndShade = 0

                    .PatternTintAndShade = 0

                End With

            End If

        Next

    End If

End Sub