While this thread is old...my Nuvi 2595 was also working just fine when I used it last in 2016, I plugged it in yesterday and Garmin Express (updated version) recognized it - said there was an update so I chose install - it stopped mid install to restart and from that point forward it is no longer recognized by my computer and I get the error via the USB does not recognize, but my Garmin 65 is still recognized via the same cord. It is frustrating and upsetting. I can still use it as it loads, but can not get it connected to anything, nor see the hard drive - that tells me it is something in the updating software for it that no longer allows the computer to see it. If it sees it and then you chose to update and it stops mid update only to not recognize it. I am upset an frustrated and nothing out there gives us an answer :-( I've thought about resetting it to factory and I have a backup of it...but I doubt that will fix it and don't want to reset everything if it doesn't restore it completely :-(
However I did get that site to come up and there is a guy "dac" on there - his instructions to click on the volume button then hold you finger in the top right of the screen until a menu pops up, scrolling down to where it says MTP and selecting "mass storage" then save. Once I shut down and turned it back on that worked and the Garmin Express found it! So thanks to people who find the hidden settings <3 this did the trick!!