… I have Update Page Layout checked in Page Layout. What else can I try? …

If I understand you correctly, you have - in the Page Layout menu - selected “Update Page Format for Score”, right?

The menu item “Update Page Format for Score” is a setting, not a command.

Perhaps the wording should have been “Automatically Update Page Format for Score”.

Try this:

Document menu > Page Format > Score…

In the dialog box Page Format for Score you can see the formatting for new pages.

You can change the settings in Page Format for Score directly.

If you do not know, what settings you need, try this:

Page Layout Tool.

While “Update Page Format for Score” is selected, go to a page where the formatting is, as you need it.

Click-select a system, and go to

Page Layout menu > Systems > Edit Margins…

In the dialog box Edit System Margins, change one of the margins.

You can e. g. change the Right margin from 0 to something else.

Then, change the margin back (not via Undo!).

Next, go to Page Format for Score.

You will see that the settings in Page Format for Score have been updated.

NB:

The setting “Update Page Format for Score” is program specific, not document specific.

You should probably de-select “Update Page Format for Score” when you are done - to avoid unwanted disasters in other documents.

That worked! Thank you very much!

And maybe someday, someone will explain to me, why this is necessary. Under what circumstances would I want a score to continue with a different page layout than I started with?

… Under what circumstances would I want a score to continue with a different page layout than I started with? …

The circumstances could be e. g. that you indent one particular system on one particular page.

Also, when “finetuning” an optimized score you might on one specific page change the Page Scaling by a few %.

A such minor layout change is barely noticeable, but it might provide space for an extra staff (with e. g. an ossia passage) in one specific system.

Possibly. But it still seems to me that under most circumstances I would want to continue as I had been, so that should be the default.

… Possibly. But it still seems to me that under most circumstances I would want to continue as I had been, so that should be the default …

In the Page Layout menu, toggle the setting “Update Page Format for Score” on.

Then, no matter how you format the first pages, all new pages will get the same formatting.