I've found a cure for Garmin Express never recognizing my Edge 800 even though I can clearly see it in My Computer. All I have to do is uninstall and then reinstall Express every time I want to upload data to Connect and it works! Easy. It takes about 20 minutes for the Garmin uninstaller to do the business each time but that's fine, I've got nothing better to do with my life.
Well done Garmin for taking about the only thing you produce that worked properly (the simple Browser plugin to upload to Connect) and replacing it with this piece of junk you call "Express" (Dictionary definition of Express is: "Rapid and having few or no stops or interruptions".....I've got a good mind to report you to The Trading Standards Authority for misrepresentation)
I can't wait for mobile phones to finally put you out of business.