I can send the file if needed. 

Yes that would be best. My address is e e biggs one at gmail dot com.  Using conventual email nomenclature and no spaces. Plus the number 1 and not "one".

thanks Ernest, sent by email, much appreciated!

Nothing received yet! Be sure to use regular email verbiage. No spaces and the number 1.

oops, I mised an e! Sent again, thanks!

nothing yet 

e e biggs 1 at gmail dot com  ---------  no spaces and use the @ for "at".

hmm, I think I got it right that time... maybe seen as spam? coming from e n r at un-labeled dot com (same rules apply)

Just to follow up in case anyone else stumbles upon this looking for an answer. Thanks a million to Ernest Biggs, above, who took my score, fixed, and sent it back in working order. What a lifesaver!

His notes to me said: "Once a file or a part or page gets corrupted there is nothing you can do to fix it. You can’t un-corrupt it! I deleted page 11" and, "You can’t delete a page unless it is blank. So all the music has to be moved before that page. Then simply use the delete blank page tool."

I have to admit, I tried to replicate this, to better understand the problem/solution for the future, and I could not figure it out. Specifically, how to move all the music to before the bad page. I tried inserting blank pages, but so far as I can tell, there's no way to flow systems onto those pages. I also tried just to squeeze the music all into the first 10 pages, but that just froze, did not seem feasible. Somehow Mr. Biggs was able to do it, so I remain grateful and slighlty befuddled. 

But I did try one other thing that made me a little nervous, but also seemed to work. I exported as musicxml, then opened up the resulting xml file in a text editor and searched for anomalous entries. Sure enough, I found one - as shown below, the measure element for staff 1, page 11 had this system-layout element that no other measures had except measure 1. I deleted that fragment and imported the xml file as a new score in Finale. It worked! That is, it fixed the layout problem. It did intropduce some other things, like I had to reset all the instruments to NotePerformer, and there were a few weird things with cross-staff notes and multi-voice measures that I had to clean up, but it did preserve almost everything as needed. 

I wish there a way to fix it in the .musx file directly - hello MakeMusic, bug tracker? - but at least I hope the above helps someone in a similar situation, or helps me remember next time I encounter this!

 I tried inserting blank pages,  ...

If you try to insert a blank page before the page with issues and/or errors Finale will insert that new blank page with the same issues and errors. Looking at your sample XLM file it appears Finale added a line that was not needed. It is almost surely the reason for the problem. Plus it is almost surely why adding a new blank page doesn't work or help.  I learned something today as I would never have thought to look at the XML.

Thanx,

EB