Voilà, tu peux changer le code de la macro par le suivant :
Sub melch()
Application.ScreenUpdating = False
derligA = Cells(Rows.Count, 1).End(xlUp).Row
For i = 2 To derligA
duree = Cells(i, 2) * 60 * 60 * 24
For j = 0 To (duree - 1)
derligI = Cells(Rows.Count, 9).End(xlUp).Row + 1
Cells(derligI, 8) = i
Cells(derligI, 9) = Format(Cells(i, 1).Value + (j / 24 / 60 / 60), "hh:mm:ss")
Cells(derligI, 10) = Cells(i, 3)
Cells(derligI, 11) = Cells(i, 4)
Cells(derligI, 12) = Cells(i, 5)
Next
Next
End Sub