Sub test()
Dim Nomdest As String, wbk As Workbook
Nomdest = ThisWorkbook.Path & "\Classeur2.xlsm" 'le classeur2 est au meme endroit que le classeur1
Application.ScreenUpdating = False
Set wbk = Workbooks.Open(Nomdest)
With wbk
.Sheets(1).Range("A1").Value = ThisWorkbook.ActiveSheet.Range("A1").Value
.Save: .Close
End With
End Sub