Is there a solution found in the meantime?
I have the same problem and cannot get the GARMIN edge 530 to connect with the laptop.
Thanks to you and meltonboy I managed to force the Edge 530 into mass-storage mode.
Maybe the last Windows update also helped.
Hpopefully next time it will work by itself. The whole handling of this GPS is more complicated than other Garmins I still use and have used in the past.