I previously had a 76CSX and just bought a new Oregon 550T. I'm trying to load my maps, waypoints, etc. from MapSource but it will only allow me to upload maps. Surely, I should be capable of uploading my waypoints... right?
I think I read there's a bug with the new version of Mapsource that creates problems with waypoints on the Oregon series. As an alternative, you could use BaseCamp which is a free download from Garmin.
See Garmin's Mapsource support forum for more info: https://forums.garmin.com/forumdisplay.php?f=181
Downloaded Basecamp and that did the trick. I have even been able to upload the data on my wifes Nuvi that I couldn't get to go before. Thanks!