Recently after reading threads concerning various anomalies with Garmin GPS units I decided to dust mine off and check it. Mine too was stuck on a certain date, 2011, and I could not get it to reset, I tried all suggestions several times, to no avail, my unit was stuck in 2011.
(As I recall I bought it as a positive backup for when I was supervising cadets on expeditions, D of E etc, an accurate fix and confirmation of location in case of emergency. I've never really wanted to or had to use it for routine navigation.)
Today I woke up and prepared for my night shift, I thought it would be a good idea to check the etrex again and maybe tinker with it tonight at work, so I switched it on.
It's now showing the correct date so I assume something happened while it was asleep!
I find all of the software and updates from Garmin to very tedious, boring, and confusing, so it's got to go.
For a device that is supposed to make life a little easier it has been nothing but an expensive, exasperating, pain in the posterior, I'll stick with map and compass.