Alright, so, the setup works, itch starts up, it installs the latest version of butler (you don’t have to “choose it from preferences”, it’s automatically used, since you have it on disk it’s using it), and you’re seeing the exact same error on login, ie. this one?
Post https://api.itch.io/login: x509: certificate signed by unknown authority.
Edit: also, what’s your exact version of macOS? I’ve seen multiple reports of this error but haven’t been able to reproduce it across multiple machines and asking specific folks to test it :/
Edit 2: I see you mentioned El Capitan earlier (my bad), unfortunately that’s exactly what one of the versions I tested earlier today.
Are you running any specific software that would “enhance the security” of your mac? I see you’re using AppCleaner, anything else?
Edit 3: If you’re comfortable with the terminal, you can try to download https://broth.itch.ovh/butler/darwin-amd64-head/45dab99ef1c1908cc18b3b86bcdb0dad78de7789/archive/default then extract it, run “chmod +x butler” if needed, and run “./butler diag –all”
Edit 4: by the way, my current theory is that the issue is linked to that Go issue - it seemed to result in a fix, hence my trying to rebuild butler with a newer Go version. There are some troubleshooting steps in there that might help you. If you find a solution, please post it here!