No help, George, just commiseration. We have been asking for a "leave it alone, dammit" setting for decades.

On a separate copy of the file, I would lock all systems (which IIRC can be done in one fell swoop) and then see what happens when you add the measure stack.

You may want to lock all systems on each player part if that is also important to you.

… messing up the layout of the rest of the score …

You are talking about the measures after the inserted measure stack (= from measure 2:53 and onwards) - right?

… I'm trying to add an extra measure after measure 2:52 (page 34) …

I can find measure 2:52 on page 36.

On page 34 I can only find the measures {2:23 – 2:32}.

* Where do you need to insert a measure stack?

As a test I inserted a measure stack before measure 2:53 (on page 37).

On page 37 the layout is already messed up (with the Score System Dividers)

After inserting the measure stack before measure 2:53 I pushed the inserted measure stack up into the previous system, but I did not see any layout changes - “messing up the layout of the rest of the score” .

* Where in the “rest of the score” did you get the layout messed up?

There is a lua script called Page Break-Every Page that will prevent any disruption of any pages after or before you insert a measure.

I change the Edit-Preferences, unchecking the Automatic Update Layout and Automatic Music Spacing boxes. Then, after inserting your extra measure, select only that line/stave/system and use Alt-L-M-N (update note spacing). Locking all systems might be a good idea.

I can't work out how to reply to a specific message!  Am I going senile?  I'm only 40.  Why is it that anything to do with Finale has the effect of making me feel I'm going senile?

I want to reply to Mike Rosen's commiseration. This is one of the most helpful comments I have received in response to a request for help relating to Finale.  At last an acknowledgement that this is not my own personal issue.  Thank you so much!  Why cannot Finale fix this?  Is THERE ANYONE OFFICIAL FROM FINALE READING THESE MESSAGE BOARDS?

Dear Adrian: 

Thanks for your suggestion.  What is IIRC?  

What does it mean to "lock all systems"?  Is that the same as adding page breaks?  The only "lock systems" I can see if in Preferences>Edit>Automatic Settings>Maintain all system locks.  I can't see anywhere else to "lock" a system.  A search in the manual brings nothing up.  

I am in any case bemused by the "Automatic Settings".  I tried every single combination of ticked and unticked boxes and it didn't seem to change the behaviour of the score.  Could you please let me know what combination of ticked and unticked boxes plus which option in the "reflow measures" drop-down menu would stop things moving around?  No combination seems to work.

What's more, the specific names of the different boxes don't seem to relate to a comprehensible behaviour in the programme.  EXAMPLE: what does the "reflow systems across pages" box actually do?  If I tick it and move a system down to the bottom of the page, I can see that it gets moved to the next page, and the subsequent systems all shift to accommodate the new position of the system.  If I untick it, and do the same maneouvre, I can see that there IS a difference in behaviour, namely that when it is ticked, I end up with three systems more neatly arranged on the following page, whereas if it is unticked, I end up with two systems more spread out on the following page.  I simply cannot relate this difference in behaviour to the concept of "reflowing systems"?  What does "flowing" a system mean anyway?  What is the rationale for the difference in behaviour between the ticked box and the unticked box?  

Adrian: I have found a function in Utilities called "Fit Measures", but that only allows you to choose a uniform number of measures for EVERY system in the piece.  Is that the "lock system" function you mentioned?

Dear Ernest: I have never heard of lua scripts.  How does one find this script and use it in Finale?  

Ian: I cannot find a "lock all systems" function anywhere.  I did have those boxes unchecked, and things were still moving around.  

P.S. Thanks to all for your replies.

George,

I hope some of us have said things that have eased your frustration, which is (if not always, at least from time to time) possible in a program as sophisticated as Finale.

IIRC means "if I recall correctly." As it happens, I did correctly recall that one can lock all systems in one fell swoop.

1. Select a measure (any measure)
2. Use CTRL-A to "Select All"
3. Then use Utilities > Lock Systems (or CTRL-L) to Lock all measures in their existing systems. (Each "line" of music is a system.) You should see a small "padlock" icon appear above and tot eh right of each locked system.

That should let one toy with one system (adding measures, perhaps) without the effects rolling over ("flowing") into subsequent systems. The system one works on may get crowded, which can be remedied later, but changes are restricted to the system being worked on.

After one is finished making changes, one can Select All and return to the Options menu to Unlock all systems and let Finale respace the music, but given what you have said at the start, I suspect you may want to leave the systems locked and handle that manually by choosing a measure (and not necessarily the final measure) of a system and pressing the down arrow to move it to the following system..

I hope some of this helps.

I have never heard of lua scripts.  How does one find this script and use it in Finale?  

This is one site that has a lot of free lua scripts. https://elbsound.studio/jw-lua-scripts.php 

There are others and some are not free.

Not knowing your expertise with Finale but lua scripts have to be installed in a certain way. They make a lot of tedious tasks easy and quick.

However adding a simple Page Break will most likely accomplish what you want.