Código de color para entradas duplicadas en un campo de Excel usando colores alternos

El proceso del que está hablando se llama 'banda duplicada'. Un par de Scripting.Dictionary los objetos deberían encargarse de esto fácilmente.

Sub colorDuplicateColor2()
    Dim d As Long, dODDs As Object, dEVNs As Object, vTMPs As Variant
    Dim bOE As Boolean
    
    Set dODDs = CreateObject("Scripting.Dictionary")
    Set dEVNs = CreateObject("Scripting.Dictionary")
    dODDs.CompareMode = vbTextCompare
    dEVNs.CompareMode = vbTextCompare
    
    With Worksheets("Sheet7")
        If .AutoFilterMode Then .AutoFilterMode = False
        
        With .Range(.Cells(1, "C"), .Cells(Rows.Count, "C").End(xlUp))
            
            With .Columns(1)
                .Cells.Interior.Pattern = xlNone
            End With
            
            With .Resize(.Rows.Count - 1, 1).Offset(1, 0)
                vTMPs = .Value2
            End With
            
            For d = LBound(vTMPs, 1) To UBound(vTMPs, 1)
                'the dictionary Items have to be strings to be used as filter criteria
                If Not (dODDs.exists(vTMPs(d, 1)) Or dEVNs.exists(vTMPs(d, 1))) Then
                    If bOE Then
                        dODDs.Item(vTMPs(d, 1)) = CStr(vTMPs(d, 1))
                    Else
                        dEVNs.Item(vTMPs(d, 1)) = CStr(vTMPs(d, 1))
                    End If
                    bOE = Not bOE
                End If
            Next d
            
            With .Columns(1)
                .AutoFilter Field:=1, Criteria1:=dODDs.Items, Operator:=xlFilterValues
                .SpecialCells(xlCellTypeVisible).Interior.Color = RGB(210, 210, 210)
                'use this to band the entire row
                '.SpecialCells(xlCellTypeVisible).EntireRow.Interior.Color = RGB(210, 210, 210)
                'use this to band the row within the UsedRange
                'Intersect(.Parent.UsedRange, .SpecialCells(xlCellTypeVisible).EntireRow).Interior.Color = RGB(210, 210, 210)
                .AutoFilter
                .AutoFilter Field:=1, Criteria1:=dEVNs.Items, Operator:=xlFilterValues
                .SpecialCells(xlCellTypeVisible).Interior.Color = RGB(255, 200, 200)
                .Cells(1).EntireRow.Interior.Pattern = xlNone
            End With
            
        End With
        
        If .AutoFilterMode Then .AutoFilterMode = False
    End With
    
    dODDs.RemoveAll: Set dODDs = Nothing
    dEVNs.RemoveAll: Set dEVNs = Nothing
    Erase vTMPs

End Sub

Los datos deben ordenarse en la columna de criterios duplicados, por supuesto.

Este proceso podría ajustarse fácilmente para filas completas o bandas de filas dentro de bloques de datos.