Activity not synced

Does the activity really show up as an "Activity" on the history widget of your watch? Generally, much safer than using the Move IQ automated acitivity detection, is timing and recording the activities manually. 

There are also other possible issues though: one of them is that your device was accidentally associated with multiple accounts (it can happen easily when you reinstall the phone app). And another user recently reported an issue where he could see his activit yon the phone app, while not on the web interface. 

To identify your case, it would help if you posted the photos or screenshot of the activity (or the empty activity list)  1) on your watch 2) on your phone and 3) on the GC Web  account

The activity really does show on the watch and was recorded using manual activation. In other words, I explicitly told the watch to start recording the outdoor activity with GPS.

trux said:

There are also other possible issues though: one of them is that your device was accidentally associated with multiple accounts

I recently bought the watch second hand and I am not sure if your point applies here. The watch notified me that it is now paired to a different account (my account) and apart from syncing the activities I do not have any other issues with it.

trux said:

To identify your case, it would help if you posted the photos or screenshot of the activity (or the empty activity list)  1) on your watch 2) on your phone and 3) on the GC Web  account

I hope describing the state is sufficient:

1. The activity is listed on the watch. I can see it in the activity history via Manual.
   After selecting the activity on the watch I can also see details of the activity like the distance covered, average heart rate, pace, number of steps etc.
2. On the phone the activity is not listed. However, the heart rate number of steps, distance (only the approximated distance coming from the number of steps and not the GPS trace) are present. It looks to me as if I wouldn't have started an activity on the watch.
3. The GC Web account shares the exact same information as the phone (point 2 from above)

A hunch for a possible explanation that I have is that I manually triggered the sync of the activity from the phone (or the watch I am not 100% sure) and didn't wait for the devices the start the sync themselves. I would still expect for the devices to also sync the activity data in this case, but maybe this is a point starting troubleshooting the possible bug at.

Are there any logs of the sync process that I can inspect?
Thank you for your help.

Well, if it is a second hand device, then there may be couple of diverse problems involved. One of them is full or dammaged storage on the watch, meaning the FIT file containing the activity is corrupted.

You can verify it by connecting the watch to the computer, downloading the activity file from the folder //GARMIN/Activity/ and dropping it onto the Import page of Garmin Connect Web.

If it imports without errors, then the problem was likely caused by a mixup of several accounts. You would find the solution in the document Data is Missing from My Garmin Account After Syncing. 

And if you get an error when trying to import it, then it means that either the storage is full or dammaged. Cleaning up the folder //GARMIN/Activity is usually sufficien to make some room. And if it is a freshly acquired second hand device, then performing the master reset first of all, is very recommnedable.

pshare said:

Then there's this email I received from Garmin

pshare, I do not hink this case is related to yours, either, since the user cannot sync the activity at all. The symptoms are different than in your case.

pshare said:

Well, one way to tell is to try to import the activity manually from the watch and the list of activities page. If it imports, he's whole. If it says the activity is already in the db, then it's the bug that Garmin just fixed.

That's what I advised in my previous post