Thanks, all. I backed up to within an inch of my life and bit the bullet: ran the Monterey installer on my main iMac hard drive. Install went smoothly and I am now sorting through the teething problems. Had to update CCC and Little Snitch right away.

Now I'm trying to get to grips with the loss of iTunes. Two apps where I used to use one. Getting Apple TV to play my video clips is proving to be a slog. I suppose I'll have to read some instructions, dammit. Anyway, seems pretty snappy. Loads of new noises and notifications to get used to.

I used to use Quicktime 7 for video editing. I'm trying to work out if the new Quicktime is as useful? Again, instruction manual...

Cheers for now,
Jerry


iMac (19,1, 3.1 GHz i5, 12.7.4, 40 Gb RAM); MacBook Air (1.8 Ghz, 8 Gb RAM, 10.14.6, 256 Gb SSD) Vodafone router and Devolo Wi-Fi Extender, Canon TS8351 printer/scanner.