optimus_nz,
>Anyway can I lock [it] that so they can't change it?
Place the following sub in the Thisworkbook VBA code module:
Private Sub Workbook_Open()
'Greys out the ShareWorkbook menu item
CommandBars(1).Controls(6).Controls(4).Enabled = False
End Sub
It will 'grey-out' the Tools/Shareworkbook menu item. Having done that it would be sensible to protect the VBA project so that someone cannot disable the macro.
Hope that helps
Patrick