I switched to the modern interface. Looks like that was a big mistake. The next time I tried to sync my Forerunner 310XT with Garmin Connect, everything appeared to go smoothly until I navigated to Garmin Connect and found nothing new in activities. I switched back to classic, created a junk 10s activity, synced and the junk activity uploaded fine. However, the real activities that have occurred since switching to Modern, though still on the Forerunner 310XT, can't be uploaded. Is there anyway to tell Garmin Express to reload upload these activities?
Found a solution to my problem on the forums and don't believe it hadn't anything to do with the modern interface afterall. I needed to apply an update to Garmin Express, though I have it set to install updates automatically, and then on the FR 310XT go to Mode > History and scroll up to Transfer All. Then, all activities were uploaded without issue.
New device and still trying to figure out all the nuances with it.
