Odd error message

Keep in mind that missing fonts can be in unused catalog entries, as well as master pages and reference pages. 

Create a MIF file and search it for fonts that show as missing in your error logs and book update messages.

To expand on @Winfried Reng  's response, after upgrading Fm, all the alert messages reset. That usually means that 'missing resource" messages, and messages about older Fm files will pop up, preventing your book update from completing successfully.

His advice to open all book files is a quick temporary fix, and if the only alert messages were related to older Fm files, saving all files in the book should resolve the issue.

Hi Bjørn,

Yes. Nongenerated files are the regular FrameMaker files.

When these files cannot be opened during the update, then something went wrong.

Could you open all files and then update your book?

Then you could close all files and check, if you now can update the book.

I am still on 17.0.3, as later versions do not support FrameScript which I need for some processes.

Best regards, Winfried