Same with 3.10 and Catalina for me. Line6 advised to reinstall HX Edit and try with no other applications running. When I originally upgraded Helix and HD Edit, I got a new cable as the old one did not connect. The new cable allowed me to update, and it reconnected after coming up......but.....It advised me to factory reset. I did this, and got a bunch of different presets,......but.....ever since that day, I've not been able to connect. I tried installing 3.1 also. Has anyone not having luck previously had any luck since the last posts? I'm so very sad not having my Randy Rhodes setting anymore.