Garmin Express keeps failing to update at 99%! It's incredibly frustrating! I tried using Garmin Map Updater and any other method possible. I would rather not do it, but I think I'm going to have to try find the .img file to put onto a microSD card. Maybe before doing that, I'll try restarting the computer and trying it again.
I am sorry that you are having trouble updating your maps. Which device are you trying to update? If it is your nuvi 1450LMT, I would recommend running a check disk on the device or memory card as there may be some corruption.
If this is happening with your 2598LMTHD, it is possible that this is a space issue. This should really never happen because Express should give you other options so make sure that Garmin Express is up to date. If you are having this problem with the latest version of Express, try deleting some unused languages out of the Voice folder on the device. If it is an issue with insufficient storage, this should free up enough space to get the last 1% onto the device.
