Option Explicit
Private Sub Worksheet_Activate()
Dim T(), L&, C&
T = Feuil1.UsedRange.Value
For L = 2 To UBound(T, 1): For C = 1 To UBound(T, 2)
If VarType(T(L, C)) = vbString Then T(L, C) = CDate(Replace(T(L, C), ".", ""))
Next C, L
Me.Cells.Clear
Me.Cells(2, "A").Resize(UBound(T, 1) - 1, UBound(T, 2)).NumberFormat = "m/d/yyyy h:mm"
Me.Cells(1, "A").Resize(UBound(T, 1), UBound(T, 2)).Value2 = T
End Sub