My 910XT has been failing syncs for over a week now. Of course it doesn't say why. No lost data that I know of. Nothing changed on my end to cause this (unless a ANT stick went bad). Reinstalled Express software, double checked all settings. After all that failed like 80 times, I even installed the old ANT Agent. First sync failed quickly, then the second (36 minutes later) failed with 2% remaining.
If I'm being completely honest, getting pretty fed up with the whole Garmin Connect experience the last few months, and I'm hardly the only one. I have to help athletes on almost a daily basis get this working after I sell it to them (which is embarrassing). I can't even imagine what you poor tech support people are going through. I typically embrace new things and software, but Garmin has bitten off way more than they can chew lately. Can someone ask the Garmin brass to focus on making existing things work and exercise trickle in implementation, rather than trying to bulk add features to keep up with the Joneses?