hi there,
both my wife and I have a 310xt - mine works 100% as intended with garmin connect (windows vista, fully updated, latest garmin firmware etc...)
hers on the otherhand always comes up with an error described as "unsupported server error" since new (over a month now). At first I put it down to trying to upload from two devices on one PC, however this is not the case since we have now installed the second ant+ dongle on another computer and get the same error. we tried a hard reset, but no change and as the device pairing works and the data is downloaded, I don;t think it is due to the hardware (either watch or dongle) - but after completing the download, the error pops up. More than a month of training data is now on the watch, I don't want to lose it!
any advise greatly appreciated!