After a complete breakdown, when I tried every other option. I was forced to do a reset: lap and start button, then turn device on, release lap and start button.
Great news is I reset and cleared the problem, not so great news, as expected. - all data and settings removed. So I have set garmin up with all my bike profiles and activity settings/training pages but what I want to know is: what happens when I sync my unit to my account. Will I retain all history; 3 years of touring that I don't want to lose, it will it simply sync forwards from the mew rides? Too scared to plug it in or turn on Bluetooth until I can be sure I won't lose my ride history..please can someone advise?