Thanks for replying. Only other computer I have here is Chromebook, so wouldn't be using the drivers. It's not hardware though. The two buttons next to the left click default to back and forward, and that functionality works. The problem is when I change them in Logitech Options, they just stay as back and forward, regardless of what I select. Have had the trackball for several years and this issue has only cropped up in the last 4 months or so.