Option Explicit
Private Sub Worksheet_Activate()
Dim CelFich As Range, CelBase As Range
On Error Resume Next
For Each CelFich In Cells.SpecialCells(xlCellTypeFormulas)
Set CelBase = Application.Range(Mid$(CelFich.Formula, 2))
CelFich.Value = CelBase.Value
CelBase.Formula = "=" & CelFich.Address(True, True, xlA1, True)
Next CelFich
End Sub