Private Sub Workbook_Open()
'***Suppose que la liste des personnes autorisées figure dans la Feuille "Registre" en colonne A
Dim Autor As String, AutorOK As String
Autor = Application.UserName
Set AutorOK = Worksheets("Registre").Range("a1:a500").Find(Autor)
If Not c Is Nothing Then
Sheets(1).CommandButton1.Visible = True
Else
Sheets(1).CommandButton1.Visible = False
End If
End Sub