I currently use a Garmin Oregon 550T along with Max OSX Lion, Basecamp, MapInstall and MapManager.
Back in August I downloaded a .gmapi file containing the maps for a particular country. Installed it no problems whatsoever.
I have recently downloaded further .gmapi files for a couple of different countries. When I go to MapManager and install them, it comes up with the usual question asking me if I want to install, so I click install. It tells me that it has installed ok. Everything seems ok so far…
Anyway, when I go to MapInstall I select my connected device and click next. Then on the next page in the drop down arrow to select maps, the only map available to me is the one I installed back in August; OSM World Routable (12-08-2011).gmapi. It does not even show that I have the other maps installed on the computer. They are a similar name but have a -1, -2 and -3 after the date e.g.; OSM World Routable (30-09-2011)-1.gmapi.
Can anyone advise me how I load all these maps on to my device?
Also, if you are downloading from http://garmin.openstreetmap.nl/ you realize that the Family ID’s and map names are re-used so it is possible that BC is only seeing the oldest. I’d suggest deleting or uninstalling, but I don’t know how that works on a Mac.
You also might try downloading a Mac map from another site like GPSfiledepot.com and see if it loads. It won’t have the map name re-use issues that http://garmin.openstreetmap.nl/ has because the maps aren’t generated from a script.