… I wonder if the command Show empty staves works with all the staves at once …

It works for me.

Did you select everything first?

You can use the Selection Tool to select everything.

Then, switch to the Staff Tool.

yes Peter, I did as you suggest...

ok, but many resulting pages (that have music) are white with no displayed music even after Update layout and redraw screen

… many resulting pages (that have music) are white with no displayed music even after Update layout and redraw screen …

This sounds like a separate issue, not an issue with Show Empty Staves.

Ideas for possible culprits:

a) Staff Styles could be the cause.

I would make a duplicate copy of the Finale document, and try to fix the duplicate copy.

You can return to the original Finale document in case something goes wrong in the duplicate.

In the duplicate copy, clear all Staff Styles.

Does that solve the problem?

b) File corruption could be the cause.

An indication could be that you experience crashes when working on this particular document.

A solution that often works, is to export as MusicXML, and then import the MusicXML into a fresh, new document.