Montana 700i downgraded to 10.50 and impossible to re upgrade to 13.20

Garmin Express is the correct software to update this device. BaseCamp doesn't know what a Montana 7x0 is. WebUpdater may have done more damage than good. You may have to do a manual update if Express is not successful,  or you can connect the Montana 7x0 to Wi-Fi and let it load the update in the background.

Thanks. How do I recover from that? I mean my MacBook doesn't see the Montana as a drive, Garmin Basecamp doesn't see it anymore (not even as a drive) and Express is happy with software 10.50. It looks like my device is condemned to remain on 10.50 forever.

I'm frustrated that Garmin pushes customers in different directions.

Google 'GPSrChive' and you will find instructions for manually getting your Montana back to current firmware version. 

Hi, I recently went through your experience and had to get a replacement device.  The basecamp updater did something to my original device, which was borderline useless.  

Eventually my device re-updated to 13.20 over wifi. updater is crap! 
However, I had my device replaced… I now have my 4th device… and still having issues! I’m either very unlucky or the device design is fundamentally flawed

You can replace it twenty more times and viting will change. 

The very definition of insanity, doing the same thing over and over while expecting different results each time. 

The hardware is great. 

The software needs more work still.

I became insane indeed, because of the device!

are you saying that we should just get along with the issues? I wouldn’t mind if it was only affecting the device but unfortunately I can’t use it with BaseCamp as it doesn’t allow it to see it as a navigation device, only as a storage device

You will have to work with what you have until the next firmware release. There is nothing else you or Garmin can do in the interim. 

Eventually, the device itself started acting up.  It got to the point where I would only see block grids on my map view.