I have 100K topo loaded on my Etrex20 and I'm unable to view the maps in Basecamp when my device is plugged into my computer. I can only see the basic world map, any advice here?

I get a message that "no unlocked maps were found on this device" but the 100k works fine on the GPS.

Should work. I know this answer does not help much, but it may have more to do with your computer settings.
Win 7, Win8.1, Win10 based machines I own display the 100K and other preloaded Garmin maps fine when connected. All I need to do is start Basecamp and connect the GPS via USB. Maps then show on the map drop-down menu and can be viewed.


butthead

Thanks Ken, nothing doing in the drop down. Basecamp reads all other info from my device it seems, just not the 100k. I've even tried swearing at my screen.

The investigation continues, thanks for the reply.

Though it is from 4 years back, there may be something of note in this thread. Or, spend some time checking out other posts on that same very helpful forum.