2018 Vulcano Black Giulia Quadrifoglio
Oh that's good to knowNo, OSX is NOT the culprit. Alfa incorrectly states on the FCA nav download site the the flash drive must be formatted either NTFS or exFAT for Alfa Romeos, which is ABSOLUTELY NOT TRUE!!
On a flash drive formatted for OSX journaled, load only these two files: USA_Canada_and_Mexico-102913.meta.dct and MAP50231.bin and nothing else. Wingler took a screen shot of this not too ago, but that's all you need to do.
I tried unsuccessfully to upload the new maps by unzipping the files and doing the NTFS/ex FAT formatting, and it wouldn't work. Unfortunately, I'd deleted my previous map update "file" before downloading the latest, forgetting how to do it in the process. FCA's wording describing the process is ridiculously incorrect and complex, whereas the actual process is bog-simple!