Groove Agent 4.2 freezes after upgrade to Cubase 10

Mac. No cracked software or VST’s
Just upgraded from a perfectly working 9.5 to Cubase 10.
Any project using Groove Agent freezes.
Groove Agent standalone freezes.
Creating a new project and using Groove Agent SE is fine
Also: each time I start Cubase, it asks me to register.

Help! Is there a way to roll back to 9.5? I can’t work without Groove Agent

I reinstalled Groove Agent 4, but that didn’t work.
Desperate to start working again, I bought the upgrade to GA5.
Installed Groove Agent 5 and all was back to normal.