I have a Mac Computer and have been using my edge 520 with no difficulty. Suddenly it won't recognise my device any more. So I re-uploaded Garmin Express for Mac and then went through the steps to get it to recognise my device. It simply will not. I have followed the instructions to a "T" but it makes no difference. So I have tried other forms of download and it simply will not happen. I don't think that there's a problem with the input USB : It charges with no problems so the USB cannot be defunct. Getting desperate as I have a month load of activities that I want to upload.
Possible the cable has gone bad, it could still charge but not supply the data needed. Does your device show as a drive on your mac?
Thanks so much: I've tried different cables and even bought a new one. Not working. I cannot see the device on the Mac although previously it was there. I am sure there is a problem with the Garmin in that I cannot load itnto a laptop device either. It charges but that's all.
If you have a magnifying glass (or young eyes…) you could try looking inside the connector to see if any of the pins are bent or broken / missing. Power and ground, which appear to be intact for you, are the outer-most pins on micro USB connectors. Data is transmitted on the center two and both must be intact for it to work.
I've been syncing using Garmin Express on my Mac flawlessly. Today I connected my 510 and Express won't recognize it as connected, while it is clearly visible in Finder. Also, the 510 unit itself indicates that it's connected to the Mac.
I am sorry that you are both having communication issues with your Edge devices. Please make sure that you have tried the steps here: Garmin mass storage or MTP device not detected by Garmin Mac applications
Also, keep in mind that many USB cables are charging only cables so if you purchase a cable, make sure it is a data transfer cable (they should say something on the package about transferring files or syncing). If you are still having trouble, please contact Product Support.