Yes, a screen shot might help.

So this is the mode by default which works fine and below in page mode

What happens if you set up a new document, and copy the score into that? Have you tried other options in the page view?

It works fine when doing that !

Option like the one in the first screen?

Just out of curiosity, I would like to see what the original file's page view looks like with

1. Systems unlocked
2. Staff size (%) checked and set, if necessary, to 100%.
3. Staff spacing checked
4. System spacing checked

Can you guide me please I did not find how to do that

Ciao, quello che penso di vedere è una parte.
Prova a eliminare la parte e quindi a ricrearla.
Può essere che questo è il modo in cui ti accontenti.

There are a number of ways you can do it, but I guess the most direct way is using the "Page Format" dialog box.

This is what you should have. The "Staff Height" is the Finale default settings measured in EVPUs:

You will need to "Redefine Pages" using the "Page Layout Tool" after clicking "OK:

You may need to do the same thing for the "Parts."

To remove system locks, hit CTRL-SHIFT+U while in the "Selection Tool."

Thank you very much. I don't have the "page layout" menu, how can I display it?

Click on the "Page Layout Tool" icon. It looks like a piece of paper.

… I don't have the "page layout" menu, how can I display it? …

Jérémy Verner,

In your screen shot above you have the Page Layout Tool icon at the right end of the palette, just next to the % icon.

It works ! Thank you all for your time, it's great ! :)