Have you embedded fonts when saving and are you viewing the PDF on the same machine, or one with the identical font(s) (name(s))?
I doubt whether it helps, but there seem to be some strange possible issues when Missing Glyph Protection is ticked in the Preferences.
I am opening file on the same machine. I have create new file, and type 2 line with č,ć,ž (fonts that I am use in this file)...save as PDF and it's work great. But no luck with this
whan i change in AI file form Schneidler BT to Myriad Pro, and save as PDF than i see all letters (but i need this font )
Is it a free version of the font?
There may be issues, especially with free fonts.
Illy is particularly particular, but it normally it would show up in the original document, not in the PDF.
I fix my problem. Open print setup and instead of my IP4300 put Adobe PDF and now all works fine
thnx Jacob for help
And thank you, Boris, for posting the solution. It will be remembered so it may help others.