Over the past year, Garmin has stopped supporting their Communicator plug-in. Many popular browsers (Google Chrome, Mozilla Firefox) have taken steps to disable and eliminate the plug-in framework that the Communicator uses. As a result, the Communicator plug-in has become unreliable and problematic for thousands of Strava athletes.
For this reason, Strava will stop supporting the Garmin Communicator plug-in as an upload method on June 30, 2015. We encourage all Garmin users to link their Garmin Connect and Strava accounts and use Garmin Express for uploading their activities. Learn more here.
Alternatively, users of some USB-compatible Garmin Edge devices may still upload their activity files (.fit, .gpx, .tcx) directly.