Please specify the steps you've already taken, so that we can rule out things.

Have you - e. g. -

quit Finale, and launched Finale again?

re-booted the computer?

trashed the Finale preferences file?

&c.

&c.

The better we understand, the better we can help.

Error occurred. ID = -1

is a generic Mac OS error. Either Finale can't find or doesn't have permissions to write to a particular directory—often because it hasn't been created yet.

Please follow Peter's steps and let us know if you still have a problem.

Have done all this and still can’t save files. Have left tech support messages. Am getting a different error message.
"While attempting to access "VI Letter from Abigail.musx.zip" the file manager reported an error. Finale - Error occurred. ID = -5". Very frustrating to watch the hours and days tick by, unable to make deadlines .....

What Mac do you have? Be specific?

Mechanical, solid state or fusion drive?

Did you install into the default location or another?

Where are your files stored? Boot drive, external, cloud or?

Can you navigate to your files? If so, what is the path?

If you find a file and double-click, what happens?

Your errors are being reported by the OS, not Finale. These errors are often indicators of hardware problems but not always.

http://www.cs.cmu.edu/afs/cs/user/lenzo/html/mac_errors.html