Wow, thank you--I'm fairly sure I'd gotten rid of it completely, but I'll try again. At the moment I haven't got a /Library/Frameworks/Mono.framework/ at all, because I've since removed it again (via the instructions at the bottom of
https://www.mono-project.com/docs/ab...atforms/macos/), which is perhaps a good sign. I'll keep at it and come back.