Mac won't recognise 645M

See https://forums.garmin.com/sports-fitness/running-multisport/f/forerunner-645-645-m/147884/mounting-on-a-mac/819295#819295

The 645m looks like a media device, and Apple only supports their own brand.  Read the thread as there are a couple options.

You can't run GE at the same time you're running one of the other options so maybe that's it.

What a complete joke. Are you saying that you have to have a Windows PC to be able to use the music function of the 645M normally?

No, you can use something like Android File Transfer: https://www.android.com/filetransfer/.  Apple only has native support for their music device. 

It's really an issue where Apple doesn't play nice with others, as you don't need anything special with Windows or Linux.  It's the same for all Garmin watches with music, and even your basic MP3 players.

It should show in Garmin Express. Sometimes it takes a while.

I had it working in Garmin Express on my Macbook Pro before and managed to sync one of my iTunes playlists. I think something has changed since an update to either the watch software or Mac OS that is preventing Garmin Express from recognising the watch when plugged into the USB-C port via the adaptor.

Which is better then - Android File Transfer or SyncMate?

Garmin Express seems to install its own USB driver for the FR645M, which is to be expected as the watch has custom functionality.  Things I look for / try when it is not connecting:

- check in 'about this mac' -> system report -> USB that the watch is listed.  If so, and other things below check out, just wait up to 3 minutes.

- no other custom USB driver software can be running - check under System Preferences -> Users & Groups -> Login items for what's starting up.  In particular, as Garmin Express usually detects now, Android File Transfer cannot be running.  These things like to run in the background all the time to detect when their special device gets plugged in.

- plug directly into the mac, not any hubs.  This isn't consistent for me, sometimes it works reliably on the keyboard USB (which is USB 2 on my system while all the others are USB 3; pretty sure the watch is USB 2).  Ususally this gets it working, but GE still needs a minute or two.

- full shutdown - power off - 15-30 sec wait - reboot cycle (after confirming no login items to start other USB drivers) to fully reset the USB hardware.

Since it is the one extra item, I would be suspicious of the USB-C adapter in your configuration.  I'd try finding another one to swap, if possible.

Also in response to another respondent, I've not tried but the problem with using Android File Transfer to set up your FR645M media seems like you have to ensure that the file structure is just right for the way the watch software expects it.  OTOH, Android File Transfer does seem to work a little better at detecting the watch and it gives you full access to all the directories to set things up as you want.

Tried both and they didn't work, watch won't go into media storage mode