I purchased the Europe NT maps on an SD card to use on my nüvi 57 (which has North America maps preinstalled). I'm using Mac to install the maps. I installed the GCP to use with Safari. (Garmin Express is also installed on this computer if this is of any relevance.) The OS X firewall is off. The SD card is formatted in FAT32.
After this is set, I go to myGarmin, myMaps, where I get a link to download the new maps. It checks a couple of things, tells me there's not enough space in the Garmin device, lets me choose the SD card to install there. Once this is selected and the terms and conditions accepted, the download begins. It increments slowly and with hiccups (which make the download "fail" and need that I press a "Continue" button to resume where it left). If during this process it doesn't stall, and I've tried this many times, it reaches 50%. After this, it goes to 0% again, and the nightmare begins anew.
I've read through a number of posts on this forum with the same problem, most of which don't report a solution. Where there was a solution, I've tried it (e.g., try having the SD card in a different USB port instead of inside the Garmin device, try downloading to a USB stick, firewall on, firewall off...) Nothing changes the failure at the end.
I've contacted the Garmin support and their suggestion was to turn ON the plugin for all pages. This only seems to make the plugin behave weirdly (plugin not detected at my.garmin.com or resuming download stalled at "Checking compatibility..."), but I've tried it and it isn't making any progress in the best of cases.
I'm doing this over a Wifi connection. I've seen that this could be a problem, but unfortunately my computer doesn't have an ethernet port (as most computers nowadays). The connection is otherwise quite reliable and fast at 100Mbps, and I've downloaded far larger files over this without a single problem, in less time than it takes this to reach 50%.
I would really appreciate any suggestions on how to proceed to get these maps on the device, as I'm going on a trip in a few hours and need the navigation. Thanks!