We need to know more. If a reboot doesn't fix you up, try a Safe Boot. This works a lot of the time. BTW, contrary to the following support doc, most non-Apple apps do not work in Safe Mode so I don't bother trying. When done, just reboot normally.

https://support.apple.com/en-us/HT201262

If still having issues, tell us what we need to know:

https://makemusic.zendesk.com/hc/en-us/community/posts/215729367-General-Discussion-House-Rules

Mike thanks for reply, 

unfortunately your suggestion does not fix my problem.

I'm on MacOS 10.13.6, iMac, Finale 25.5.0.259.

I it can help, I attach the screenshot of the message I receive if I try to select MusicXML preferences:

It's telling you to reinstall Finale. It doesn't hurt anything to do so. Download from your MM User account and re-run the installer.

Solved thanks!!! The reinstallation fix the problem.