Is there a Page Break showing? How did you add the extra systems?

There is no page break to be seen. After importing the XML file (one staff, violin 1), I went to Scroll view, chose the Staff tool, and double clicked four times below the first staff to create four more staffs (3 more violin parts and a cello part). I then copy-pasted notation for the other parts from four more imported XML files. It all looks fine in Scroll view, and the staves are grouped with a bracket (2nd from rightmost option). However, when I switch to Page view, only the initial staff (violin 1) shows.

I was able to work around the issue by creating a new Finale document with the five staves in place and then copying-pasting the notation into the empty staves. However, I'd like to understand why the method I first used didn't work. Perhaps it's something that Finale just won't do?

p.s. I realize I used the term "system" in my first post where I should have used "staff." Sorry if that caused any confusion.

I always add my extra staves in Score Manager. Maybe that's the difference.

I don't think so. I went into the Score Manager to see if there was some setting that could be changed there. All five parts were listed and named.

I've just tried an experiment to see if I could duplicate the issue: I couldn't. I followed the same procedure I described above: imported a single-part XML file, went to Scroll view and Staff tool, double-clicked four more new staves below the first. When I went back to Page view, everything showed up.

I also created a new one-part document through the set-up wizard and then added more parts in Scroll view. Again no problem, all parts appeared in Page view. I still have no idea what caused the problem in the first document, but bottom line, it's apparently not an application bug, which is a relief.

I think im having a similar issue when importing a MusXML into my string template. But I lose staves in scroll view after import. (*Also losing the ability to Explode music to now missing staves in BOTH Page and Scroll views)??

Template:  6 staves in page and scroll view (and the ability to Explode music)

XML file: Logic Pro X > MusXML file (grand staff)

Any help greatly appreciated