Finale 2007 was developed in summer 2006.

And so was the Finale 2007 installer program.

The 2007 installer can not run on Big Sur.

Even if you should somehow manage to get Finale 2007 installed in Big Sur, you will have trouble making Finale 2007 run in Big Sur.

You can definitely not use Human Playback (not without crash) with Finale 2007 in Big Sur, and you will also find issues with the Expression Tool.

Solutions:

Either upgrade Finale (= what I would do)

or downgrade Mac OS to an earlier Mac OS version that supports Finale 2007.

Thank you very much for your early reply.One more question: what do you mean by upgrade Finale? I have to buy a new ( latest) one e.g. v26 or else? and get rid of my old one?

Yes, I am pretty sure Peter means that you should upgrade to Finale 26. Check their page (finalemusic.com) to see if they have a special upgrade price.

If you do upgrade, you should be sure to back up your old Finale .mus files, which a new version will need to update to a newer format .musx when you open them. You will also want to set aside time to learn the changes that have been instituted in Finale since 2007. Finale 2012 was in itself a big change (in Expressions, in particular).

Big Sur is 64-bit ONLY. And only F26 is fully compatible.