Fixing WiFi on Garmin 840

It’s been a very long time since my last post, so I thought this might be helpful to someone.
It took me way too long to figure everything out.

When setting up the wifi on the 840 via the device or the companion app it leaves the security protocol (WPA/WEP/open) blank. As a result, it will not authenticate and wifi is crippled.

You can select the proper security protocol when using Garmin Express.
So get your computer, install Garmin Express, and plug in the device via USB.
After registering with Garmin Express, go to Tools, and selected existing wifi network.
From here you can select the security protocol.

On Windows, I did WPA2 and and stayed on the network for a day.
On Mac, I did 1 network on WPA and another on WPA2 and it has worked consistently since then.

To connect the 840 to a Mac you must power off the device AND close Garmin Express.
First, plug in the 840 and let it enter network mode.
After about a minute, open Garmin Express and pair the device.