There was an error installing the update.

Have you checked that your firewall or 'ghostery' or similar are not blocking the download?

Have you checked that your firewall or 'ghostery' or similar are not blocking the download?

No third party firewalls are active.

To be clear, the Garmin Express software did download and install on my Mac. The issue is with downloading and installing the maps using Garmin Express software.

There are a lot of problems with Garmin Express 4.0.8.0, even on windows. Go back to a older Express version, and try back. This is the way to succes

Express v4.0.8 downloaded the recent CN EU 2015.40 for me without issue.

Then you are lucky. At Dutch Garmin fora, almost everybody on mac and pc got problems downloading 2015.40 with version 4.0.8

I have a Nuvi 3590; I'm running OS X 10.10.2 and Garmin Express 4.0.8.0 and it is, without doubt, the biggest pile of poo I have encountered in 30 years of programming and software development. I've managed to update the system software on the device using Express, but updating my maps is impossible. I have a 30mbs download speed, but Express first of all tells me the map update will not actually take four hours, as originally estimated, but over 4,000. Then the fans on my 2014 Retina 15in MacBook Pro go flat out, Garmin Express Service hogs nearly 200% of my CPU, and finally I get a message saying there's been an error (unspecified) and it stops the so-called update. This is a joke in extremely bad taste ... how Garmin can keep a straight face with this level of quality is beyond belief.
I'm prepared to try a previous version of Express if that's what it takes to do a simple task such as updating my maps, but Garmin don't make previous versions available for download. Or do they? Perhaps someone could point me in the right direction?

Here you can find anything for Mac and Pc : http://www.gawisp.com/perry/macintosh/ Just scroll down for Express, under BC.

Thank-you. I've gone to your link, but all the file names have been truncated, so it impossible to know which version of Express to download. Can you be more specific please? Also, what does 'BC' mean?

Release of 25-Jun-2014 is good one. Version 3.2.8