I have a GPSmap62s used for mountain biking.
The issue I want to discuss in this thread is waypoint and track files that are on my 62s but will not display.
At first I thought the issue was related to files that I had opened, modified, and saved using Basecamp. I've had trouble uploading tracks to Garmin Connect and found this thread in the forums. https://forums.garmin.com/showthread.php?t=22805
I've used Notepad++ as discussed in that forum to correct the encoding so that I could then upload them to Connect.
I also discovered at the same time, that I had files on my 62s which would not display in Track Manager. I discovered that once I opened them in Notepad++, and corrected the encoding, they would then display correctly on the unit. I thought that this issue was the result of opening them in Basecamp.
I have recently discovered that after being connected to my PC (I always use the "eject" for a USB before disconnecting the 62s) that some or all of my gpx files would no longer display on the unit. Yesterday all 41 track files, and several waypoint files would not display anymore. Had to laboriously open them all in Notepad++ to correct it.