William, many thanks for all your effort and advice. Tbh it all sounds even more daunting now!
Things were looking good till I got to your 4th para – I’d be worried about Security.
My Mac runs OS 10.11.6 (El Capitan) so does that mean I have the same problem as you mentioned with Catalina?
I like the idea of partitioning and running Windows as a workaround – the only problem is my whole HDD is only 250Gb!
Sorry, but I do not understand the language in your last para – what does “notarised” mean…I fear I just won’t know WHAT to do.
I just want to acquire data with the ZWO 290MC. I’m a Physicist not an IT whizz!
Anyway, many thanks, Paul