back disc wont stay on

Hi Traci, I assume you are not referring to the complete back cover (which is fixed with four screws) but to the smaller lid in the middle of the back cover, which is glued?

Even though my Active 2 was only one year old, I had the same issue. I googled a bit and found out it is a common problem - though Samsung usually seems to deny it and claims this was caused by contact with water (funny as this watch is sold as water-resistant). So even as this should be covered by warranty, they refuse to repair it for free. As for myself, I decided not to get upset about this but instead just order a new self-adhesive gasket from an online shop (cost is approx. € 6,- with shipping already included). Once I received the spare part, I cleaned the watch and the lid from the old glue. Then, I first pressed the spare part concentrically on the lid, removed the green protective film and pressed the lid into the back cover.

If you’re not too awkward, I would recommend the same to you. It’s not difficult, but of course you have to be careful not to destroy anything inside the watch. So of course, I can’t take any responsibility and if you try to repair it, you do this at your own risk. Good luck!