Kontakt - instrument not initialised

Hello,

I've opened a score after a few month without working on it. It's a piece where there's strings and I had it set up with Spitfire's Chamber Strings. I worked on it like that with no problem for almost years I'd say. Now Kontakt won't open Spitfire's libraries and I get that message. I've tried other libraries and there's no such message but still no sound coming out of Kontakt. I guess it's my bad for letting MuseScore upgrade and upgrade all the time when everything worked out fine. Now, of course, if I try to go back to a previous version of MuseScore, I get the error that the score was edited with a more recent version of MuseScore so I can't open it. This looks to my like a trap. Upgrade, and if it doesn't work out, too bad, you won't be able to go back.

I've searched online and in this forum and I don't seem to see a lot of information on this or a solution. There's some similar issues but they are a few months old, or years, and since those were made I feel I have upgraded 100 times MuseScore.

Can anyone throw some light on this? If it has been discussed and I haven't been able to find it, my apologies. I have tried to close, restart, reboot, reinstall, uninstall, all the classics.

I'm on the latest version of Sonoma 14.5.

Thanks