Hi Karl,
I have run into this issue also, but no work-arounds seem to be fixing the problem, and I just can't seem to figure out what could be "corrupt."
It started with third party PDFs, then became almost all PDFs that began their lives as either InDesign (CC) files or Keynote (6.5.3) files. This began when I had Acrobat X, and is continuing now that I have Acrobat XI. In fact, a lot of people in my office have run into the issue, some files open just fine for some people, then don't open for others and there is no real pattern to the madness.
Our office is made up primarily of mac computers. We all have the most up to date Creative Cloud, Acrobat and Keynote, we also all share fonts on a universal type client. Whenever we export to PDF and open those PDFs with Acrobat XI, those PDFs show up with blank spaces where some of the text should be, and an error is shown saying that the embedded font could not be extracted. Even when I make a fresh Keynote or InDesign file from scratch the resulting PDF returns the same error. Obviously, the "use local fonts" trick doesn't work here. (I also tried extensive troubleshooting, using other computers in the office, working with people in offices we have in other countries and cities, installing fonts locally and disconnecting from the type client, etc.)
Could you please go into detail on what you think could be corrupt across all of these files? Do you think it's a Keynote issue? An InDesign issue? An issue with the fonts themselves? Perhaps something crazy going on with our entire computer network? I've tried with numerous TTF and OTF fonts with hit-or-miss results across the board. Our IT department is also baffled, and the only thing that we all unanimously agree upon is that it seems to be an Acrobat problem (unless you can prove to us otherwise!)
It might also be helpful if you could elaborate on the "more strict" guidelines for corrupted files, as I can't find any good language or explanations online. Maybe that would shed some light on our problem and lead us to a solution.
I know you're not to blame, and I would really appreciate your help on the matter. I'm just frustrated that it's become so difficult to share files in beautiful PDF format.
Thanks!
K