My Garmin GPSmap60CSx worked fine up until a year or so back, but then I found I could no longer download Caches to it from the website so stopped using it. I now wish to go back to using my Garmin GPSmap60CSx but still cannot get it to download co-ordinates. It is up to date with recent issues, I have Garmin express up to the most recent issue but still keep getting told that "Garmin Express does not support this device, please use Garmin WebUpdater" which I do but end up going round in circles
The issue with the Garmin 60csx is that it does not accept .gpx files directly. That is why you'd have to use a 3rd-party program, as HHL noted above, as an intermediary - to convert the .gpx file into a format that your 60csx can consume.
There were a lot of discussions about this when the Send to GPS button was removed, so a search of the forums might be helpful. But there was also this post in the Release Notes (Website: Downloading caches to GPS devices) - August 28, 2018 thr