I'd been syncing fine with Garmin express until April 2 this year (Garmin Edge 800). Can't remember what I did or what happened around that time, but ever since then I would get the error on Garmin Express: "There was an error syncing with Garmin Connect." None of my files were being uploaded to Garmin Connect or Strava.
I was able to manually upload directly to Garmin Connect but this is quite tedious.
just solved it this morning:
- on my Garmin device (<drive>:\Garmin\Activities) I noticed many already sync'd files had the same modified date (14 April 2015). This led me to believe there was a file corruption somewhere.
- I manually uploaded all activity files directly to Garmin Connect to ensure they were all saved
- deleted all activity files on the device <drive>:\Garmin\Activities
- reconnected the device to start the Garmin Express sync - no good same error
- deleted all activity files from the local store on the computer:
- Windows 8.1: C:\ProgramData\Garmin\CoreService\Devices\DeviceUnitID\Sync\FIT_TYPE_4
- Windows 7: C:\ProgramData\Garmin\GarminConnect\DeviceUnitID\Upload\FIT_TYPE_4
- Mac: ~user/Library/Application Support/Garmin/GarminConnect/UnitID/Upload/FIT_TYPE_4
- Windows 8.1: C:\ProgramData\Garmin\CoreService\Devices\DeviceUnitID\Sync\FIT_TYPE_4
- reconnected the device to start the Garmin Express sync - all good, sync works correctly now