I had an issue with Apple FontBook not accepting my freshly designed font.
I sent it to FontLab for a checkup. Pretty soon I got a reply from them, and they could not point to individual character, but I got a replay:"…the problem is in the CFF compression. This is a AFDKO issue I think. If you turn off the "Use subroutines to compress outlines..." option in FLS before you export FontBook will accept the font."
This was all new to me, and since I make commercial typefaces, I need to make sure they work. I got help from this forum about installing the font without FontBook, but the font; the end product, is supposed to work everywhere, so I was somewhat relieved that FontLab advise cleared the issue.
But what are these CFF compression and AFDKO? And should I know more about them?