I have a forerunner 220 and I have a mac mini. I have been unable to load data via Garmin express for some time. I keep getting server communication error messages I have followed the the troubleshooting steps in the support pages including enabling auto proxy detection and updating the time and zone settings. I am using el capitain as OSX I tried deleting my device from express an readding it. Now it can't find it even though it is plugged in and mounted.
Any suugestions welcome but I have logged a product support issue.