The login might not be your fault. I'm on Windows 10 too and have the box checked to automatically logged in, but starting sometime in the last week the vectric site keeps logging me off when I leave if I'm gone for any length of time. Other sites aren't doing it to me, just them.
I had issues with my downloads too when I first switched. It was a browser problem. I thought I had the same version of firefox, but apparently I had the windows 10 "app" version and had to spend a week trying to find the right settings to get it to look and act somewhat close to what I had before the "upgrade."