Private Sub Workbook_Open()
Dim Msg As String, Style As Integer, Title As String, Response As Integer
Dim UN As String
Dim CA As String
Dim A As Variant
Msg = "Message"
Style = vbOKOnly + vbInformation
Title = "User Box"
UN = Application.UserName
CA = "C:\Users\" & UN & "\Documents\NO BACKUP\"
Response = MsgBox(Msg, Style, Title)
If Response = vbOK Then
A = Application.GetSaveAsFilename(CA, "Fichier Excel,*.xlsx")
If A <> False Then ThisWorkbook.SaveAs A, FileFormat:=-4143
End If
End Sub