Oh have I had "fun" with Garmin Tech Support over the last couple of weeks!
First I had to buy 2 DVDs to get the 24 K areas I wanted. But the maps would not show on the device after loaded onto a 32 gb SD card.
I will not bore you with the back and forth of it, but MapInstall is a separate program from BaseCamp here is a link:
http://www8.garmin.com/support/download_details.jsp?id=3291It's best to install the separate program. MapInstall does not give you the option (like in MapSource) to install to either the internal memory, or the SD card. It will install to the internal memory till that runs out, and the overflow will go to the SD card.
So to fix that put the SD card in a card reader, with the device not connected to the 'puter.
Long and short of it my Montana will not read a 32 gb SD card. A 4 gb, an 8 gb, and a 16 gb are all fine. They have no answer. They stopped answering my emails.
Stand by for more "Fun With Garmin Support".
By the way, the maps are route-able (and not locked) and anything more than 50 way points and the unit will not calculate the route.