Hello, I recently downloaded NW trails for Mac from Switchbacks.com. I opened it with map manager and put it on my basecamps (it isn't transparent over my 100k Garmin map, which I expected). I used MapInstaller to put it on my Dakota 20 onto the SD card. It won't read the map from the SD card, although I already have Garmin 100K map saved on the SD card and it reads those maps fine. I drag and drop onto my GPSr internal storage and it reads it. Although it adds a lot of water to my maps. Zoomed all the way out 75% of the entire county is covered in water, althought NW maps is only covered in ID, OR, MT, WY, BC, AB and AK. Once zoomed in on the trails it doesn't seem to be such an issue. I can provide some screen shots if that would help?As I said it reads the 100k garmin map (consist of 5 .img files) from my SD card fine but doesn't see the NW trails map until placed on the internal storage. I've tried downloading the maps separate to the card and all at once, with the same results. I've also deleted NW Trails and redownloaded it to fix the water issue without any luck. This evening I'm going to try format my SD card in a card reader to FAT32. Master Reset my GPSr, shut off and install the SD card. Then lastly try to download the maps to the SD again.
That map is not hosted at GPSFileDepot, so you should directly contact Switchbacks.com for support. Looks like they have a forum devoted specifically to that map.
http://www.switchbacks.com/forum/index.php?board=2.0
Thank you! I'll try there.