Risolto!
Trovato il metodo su expert-exchange (copia cache )

A work-around was found for this issue. It seems once Safe Mode was used to open this database, the menus actually came back. So far they haven't disappeared again, so I'm crossing my fingers on this one. Thanks.
Just curious ... by Safe Mode, do you mean where you hold down the Control Key (as opposed to Shift Key) when opening the MDB ?
Sapevo dell'apertura dell'mdb tramite tasto shift ma ignoravo l'utilizzo del tasto ctrl per avviare access in modalità provvisoria.
Ho fatto così e la barra è ricomparsa.