FM8? 9? > FM10 errors

[Robert Lauriston]

I'm updating a project that was last updated with FM8 or 9.

Updating the book or saving as PDF fails with these errors:

Could not open [book]TOC.fm, because it uses unavailable fonts.
FrameMaker will create a new version of [book]TOC.fm. If you save this
new version, you will overwrite the existing file. To use your
existing file, close the new version without saving it. Then open and
save the existing file in Document format. Finally, update the book
again.
Could not open [chapter].fm, because it uses unavailable fonts.
FrameMaker did not update the generated files because of errors such
as: Couldn’t open [chapter].fm

If I have all the chapter files open, there are no errors and it works fine.

Is there some way to get rid of the errors? The "Remember Missing Font
Names" setting has no effect.