Hi ligfietser, thanks for the speedy reply. However a couple of years ago I downgraded to a 4.7 version of Basecamp in order to load some OSM maps onto my Garmin GPS. However last year I bought a new Mac and without thinking added the 4.8.4 version of Basecamp to it. Yesterday I found it impossible to transfer a downloaded OSM map of Italy (I’m off there on Thursday) from Basecamp to my Garmin Montana. So I assumed it was the old problem, but perhaps I was doing something else wrong then? Any tips?
Best wishes,

Bob