I have the same problem on my 2019 Ridgeline that the user below outlines - the only recommendation he got was to go to his Honda dealer, which he declined to do; I agree with that choice but wanted to post in case anyone else has a recommendation. Besides not having the same vehicle, the other difference is that my download didn't take anywhere near two hours. This is not a Honda issue - I was able to install the last update. I can check the free space on the 16GB USB drive and it has maybe 96kb of space taken, so it seems logical that Garmin Express never did in fact download the map updates to it. I don't think the user below is aware that the map updates likely were never copied.
"I very carefully followed the instructions on https://support.garmin.com/en-US/?faq=8vzoH5r1tRANWNbfmAyxvA to update the maps on my 2021 Honda Accord Touring Hybrid vehicle.
The process failed when I re-inserted my USB drive into the same USB port that I used to initialize my USB drive, this time to actually update my vehicle's maps. Rather than installing the map updates that I spent two hours downloading with Garmin Express, the Garmin app in my vehicle simply re-initialized my USB drive and told me to download the map updates to my USB drive again.
Garmin's own technical support had no answer, and told me to see my Honda dealer. I'm not going to do this, since I can't see a reason to pay my dealer because Garmin's own update process failed.
Is there any other way to get my vehicle to install the map updates that I downloaded to my USB drive? I have already spent too much time trying to get this done, so if there's no easy way to update my vehicle's maps, I'll simply forget about them and continue to rely on the Google Maps in Android Auto, which have never let me down."
