Thanks. I put the SD card into a reader and checked properties, it is a FAT32 file system. The Garmin folder is there containing the My Trails (.img), along with the NE Topo part 1 (which comes up fine).
Since it's working great from internal memory, maybe I'll just leave it, or delete the one on the SD card, do a reload, and try it again.
Since it's working great from internal memory, maybe I'll just leave it, or delete the one on the SD card, do a reload, and try it again.