Continuing the discussion from Carelink upload fails - Medtronic 670G:
So, I’ve had this same problem and may have a fix. Worked for me anyway. I read somewhere, something to the affect of “don’t try to run the download program from safari if it has started automatically” ie. when you turn on your computer, some things automatically boot - in my case Safari is one.
I don’t even know where I read it, but at my wits end, I quit Safari, then booted it manually, and it worked after numerous failed attempts, full carelink software uninstall/reinstalls, and restarts.
Hope it works for others trying to figure this out.