Installed a new 2TB SSD for my photos, as the 1TB one was extremely, unusably, full. Went without a significant hitch, amazingly. Obviously we had the issue of Windows making the new one drive G (the 1TB one was still installed, 'cos I was about to clone it to the new one) and then not making it back into F once the original was removed, thus meaning that Capture One said "where's your photos, i can't find them?). A quick trip into disk management to re-letter the drive soon sorted that. Can't have anything else being G, as otherwise Acronis will be too stupid to find its own backup drive, saying "All I can find is this drive called Acronis backup, absolutely identical to the one I usually use, but I can't use that, because it isn't G, because you've had the temerity to have a USB drive plugged in." Programs know the identity and serial number of the drive they use, so why do we still rely on (movable) drive letters?
I have not as yet re-formatted the original 1TB photo drive (a Samsung 850 Evo SSD), I'll wait a bit before I do that. It has a new future lined up as a portable drive for the archive digitisation project I expect to be doing soonish.