Hi Everyone,
This seems like a common issue for mac users and I looked a various solutions like re-installing and uninstalling garmin express which did not work.
I also did not want to hard reset my watch, so I decided to go through the hidden files that might be causing the issues.
The main folder that you want to go into is located in /Library/Application Support/Garmin/Express/RegisteredDevices
You will have a folder in there that will look like 34849842 as an example. Delete this folder, restart Garmin express and sync your watch.
Everything should sync ok now.