I've been having trouble syncing to Garmin Connect with my 910xt. Sometimes it syncs some of the files, and sometimes it says There was an error syncing with Garmin Connect. I've tried a soft reset, reinstall software, pair and unpair watch and nothing seems to work. I tried to delete some of my old data by selecting 'delete older files' but it deletes '0' which means I don't have old files. I do. Plenty of them. So, there is definitely something wrong but I don't know where to begin.
I am sorry you aren't able to sync your Forerunner 910XT. If the device can't delete the old data, it is normally because the data is corrupt. To fix this, we need to perform a Master Reset. Unfortunately, the Master Reset will erase all user data from the device, meaning anything not already uploaded will be lost. Please use the steps in the FAQ, "">How do I master reset my Forerunner 910XT?">How do I master reset my Forerunner 910XT?".
After the Master Reset process is complete, please gather some new data and then pair your device with Garmin Express again. If your device is already added to Garmin Express, please remove it so you can pair again.
To answer your question, at least part of the data is corrupt because both delete functions should work. However, if you can delete the data individually, you can first try to delete all the data that has already uploaded. This may clear the corrupt data and allow you to sync again. Then you should be able to upload the recent data.
If removing the already uploaded data does not solve the problem, then you will need to Master Reset the device as mentioned.
