Bonjour,
à tester,
Sub test()
rw1 = Cells(Rows.Count, "A").End(xlUp).Row
rw2 = Cells(Rows.Count, "B").End(xlUp).Row
For i = 1 To rw1
If IsError(Application.Match(Cells(i, 1), Range("B:B"), 0)) Then
Cells(rw2 + 1, 2) = Cells(i, 1)
rw2 = Cells(Rows.Count, "B").End(xlUp).Row
End If
Next i
End Sub