Hi Stuart, and everyone who is interested in this issue!
I was informed by our colleagues that this issue might relate to preferences. Performing a
Preferences Cleaning might help. The local partner mentioned that after reinstalling ARCHICAD, the issue went away, so this could be another solution to the slowness issue!
Thank you very much for reporting the issue to us!
Have a nice day!
Best regards,
Minh
Minh Nguyen
Technical Support Engineer
GRAPHISOFT