Ha ha, I was trying out the latest "test" iso, and it couldn't find my printer. Thing is I had installed it before on the same iso, then re-installed to test something else. After several minutes scratching my head, I checked for my scanner, as it's on the same external hub (the back of my computer has 6 sockets for 7 devices

) and it wasn't there either. I unplugged the hub, then plugged it in again.
You can guess the rest.....