I just connected my Garmin 910xt via Ant to load my last two weeks of training into Garmin Connect, but it did not load my two most recent runs, and now when I try to look at the history on the actual watch, the most recent activity it shows is from May 2014 (2 months ago). The two activities that are missing in Garmin Connect were a 27 mile run/hike and a 19 mile run/hike, so I'm not sure if the large file sizes have something to do with the issue, but any help retrieving this data would be greatly appreciated!
If you are using ANT Agent, you might be able to find the .fit files in the directory described here. If the files are there, you should be able to manually upload them via the Upload button in classic Garmin Connect (here) or via the Import link in the modern Garmin Connect (here).
It is possible that the manually upload will fail. This can happen if the .fit file is corrupt, and you may be able to use (or find someone else to use) the Fit File Repair Tool to repair the file.
