Do you find your Garmin 500 gets corrupt and loses ride data a couple of times a year? Maybe after clocks go forward / back? We have 3 Garmin 500s and I can confirm there is an issue.

Do the following procedure to ensure you don’t loose your next ride;

Power on and let Garmin locate satellites.
Start and record short ride (walk around a bit)
Stop and power off
Power on – Garmin will say ‘Working…’ for about 10 minutes, previous ride data will be lost, but it will be safe to use again now.

Pretty sure it happens when clocks go forward too but going to have to wait 6 months to check!