I have to provide my ms as a pdf; I've read a lot on this list about vector fonts etc, much of which I don't understand: but I trusted, and did it. In documents >settings > fonts I changed the values from default to Latin Modern Roman, Latin Modern Sans and Latin Modern Typewriter. The default family is Roman. The printer sent the file back as incomplete, with the following message:
Your document could not be created: The TimesNewRomanPSMT font is not embedded. The TimesNewRomanPS-BoldMT font is not embedded. The TimesNewRomanPS-ItalicMT font is not embedded. The TimesNewRomanPSMT font is not embedded. I don't understand this: surely I am using Latin Modern Roman, and it is embedded automatically? (a thought strikes me: could these font errors pertain to some pdf files I include, which are musical scores made into a pdf by Sibelius?)