I've had a lot of trouble syncing Garmin Fenix 2 activities over bluetooth using Android phone and Garmin Connect app. From Garmin Connect debug logs I saw that the activities existed but they couldn't be downloaded.. I thought that perhaps they are not flushed to Fenix 2 internal storage properly and did a restart to watch (Power off and power on again). After couple of more trial runs it seems that this method works always (as long as Garmin Connect servers are not down again).
Steps for successful Garmin activity sync:
- After finishing activity power off the Fenix 2
- Power on
- Select "Sync" from Fenix 2 menu (I use manual sync)
- Fenix 2 should start showing "Connecting"
- Turn on wifi/mobile data on phone (I only enable networking when I need it)
- Turn on bluetooth (Bluetooth is off by default too)
- After couple of seconds Fenix 2 should show "Sync In Progress"
- I start Garmin Connect app to verify that the sync is actually progressing too.
- After sync is finished turn bluetooth/networking off again.
Note that Garmin Fenix 2 sync over bluetooth is very very slow, it takes a few minutes for a half a hour of running activity to upload.