Recently I found that after about 12 months of use my Garmin Edge 500 became sluggish and slow to respond. I would press the start button and it would take 2 -3 seconds to respond or it would only start recording data after about 500 metres. If this sounds familiar try this.
Simply back up all the .fit files from your unit to your computer or delete them. Immediately the unit’s performance should return to normal and if you back the files up to your computer you can still access the data if you need to. For reference the .fit files are located in “\Garmin\Activities” of your unit.
At the time I had some 250 files taking up around 20MB of the 50MB available on the unit. In the end I’m not sure if it was just one corrupted file or just too many files that caused the problem but by removing them from the system it certainly fixed the problem.
I suspect the Edge 500, being the older mini-USB, is communicating at only USB 1.1 speeds (as opposed to USB 2 or 3).
When you’re uploading to Garmin Connect or Strava, the plugin needs to parse all of your .FIT files to find unprocessed ones. Likewise, on startup the device is almost certainly scanning its internal storage at some godawfully slow speed.
So, yes, I regularly back up/delete activities on my Edge 500. It certainly makes all the difference.