So it turns out that too many people were having problems with HTC Sync and HTC & Telstra have instead decided to push the update OTA to prevent any further problems. To get the update, if you haven’t already updated, follow the instructions below.
(*menu* ->) Settings -> About phone -> System software updates -> Check now
This update needs to be done with 25MB free and use of WiFi is encouraged as the update is nearing 170MB 92MB. This should stop people having problems with HTC Sync. Once again, tell us how you go in the comments 
