Public Sub saveAttachtoDisk(itm As Outlook.MailItem)
Dim objAtt As Outlook.Attachment
Dim tamanoCadena, i, cadenaResultado, caracteresValidos As String
Dim saveFolder As String
saveFolder = "C:\Users\herna\Documents\Attachments\"
     For Each objAtt In itm.Attachments
    If ((InStr(objAtt.DisplayName, ".xml") Or InStr(objAtt.DisplayName, ".zip") or InStr(objAtt.DisplayName, ".PDF") Or InStr(objAtt.DisplayName, ".pdf"))) Then
               tamanoCadena = Len(objAtt.DisplayName)
                    If tamanoCadena > 0 Then
                         caracteresValidos = _
                         " 0123456789abcdefghijklmnñopqrstuvwxyzABCDEFGHIJKLMNÑOPQRSTUVWXYZ-_."
                          For i = 1 To tamanoCadena
                          caracterActual = Mid(cadenaTexto, i, 1)
                               If InStr(caracteresValidos, caracterActual) Then
                                   cadenaResultado = cadenaResultado & caracterActual
                              Else
                                   cadenaResultado = cadenaResultado & sustituirPor
                    End If
                         Next
     End If
              objAtt.SaveAsFile saveFolder & "\" & objAtt.DisplayName
          End If
     Next
End Sub