XL 2016 MSG spéciale

Case 0
                Msg = Msg & "La formation de " & cel.Offset(0, 3) & " " & cel.Offset(0, -3) & vbLf & _
                "est arrivée à son terme." & Chr(10)

Private Sub Workbook_Open()
Dim cel As Range
Dim Ecart As Long
Dim Msg As String
Dim derlig As Long

    With Sheets("Feuil1")
        derlig = .Range("A" & Rows.Count).End(xlUp).Row
       
        For Each cel In .Range("D2:D" & derlig)
            If DateDiff("D", Date, cel.Value) < 0 Then
                Ecart = 0
            Else
                Ecart = DateDiff("D", Date, cel.Value)
            End If
            Select Case Ecart
            Case 1 To 15
                Msg = Msg & "La formation de " & cel.Offset(0, 3) & " " & cel.Offset(0, -3) & _
                " arrive à échéance dans " & cel.Offset(0, 2) & " jours." & Chr(10)

                cel.Offset(0, 1) = cel.Offset(0, -3)
                cel.Offset(0, 1).Interior.Color = vbRed
                cel.Offset(0, 1).Font.Color = vbWhite
            Case 0
                Msg = Msg & "La formation de " & cel.Offset(0, 3) & " " & cel.Offset(0, -3) & _
                " est arrivée à son terme." & Chr(10)

                cel.Offset(0, 1).ClearContents
                cel.Offset(0, 1).Interior.Color = xlNone
                cel.Offset(0, 1).Font.Color = none
            End Select
        Next cel
        MsgBox Msg, , "FORMATION"
    End With
End Sub