I've been having major problems syncing my FR610 with Connect to upload activities and download workouts since 26/06/2014. The current error is in the attached .png file. I've also had "sync error" messages. Over the last week, I've tried many actions advised by Garmin in this forum in response to the MANY other users who are experiencing Garmin Express sync issues on a variety of devices.
Steps followed (in no particular order) are:
1. deleting the device folders in C:\Users\yourusername\AppData\Roaming\Garmin\Devices\ and C:\ProgramData\Garmin\LegacyProxy
as per suggestion by EXPRESSCUSTOMERCARE in https://forums.garmin.com/showthread.php?74931-Can-t-pair-610-to-Garmin-Express/page3
2. removing and re-installing Garmin Express 3.2.8.0
3. deleting and re-adding the device in Garmin Express 3.2.8.0
4. restarting the FR610
5. Soft reset of the FR610
6. Master reset of the FR 610
My OS is Windows 8.1 64Bit. I've not installed any other updates to my PC during this time and there have been no Microsoft Windows updates either.
Just reading other recent posts in the Garmin Express - PC section of the forum, it does seem as if 3.2.8.0 has been released before enough testing has been done. Surely Windows 8.1 and a Forerunner 610 are not really unusual combinations? I did previously use Ant+ Agent however this has been removed.