Clear Font Caches & Font Databases in Mac OS X to Resolve Unusual Font Problems
In some unusual and admittedly rare situations, fonts in OS X and various Mac apps may display erroneously, or outright fail to display. Typically this happens after a font has been modified or a font has been installed outside of the standard ~/Library/Fonts directory, but it can happen out of the blue in some situations as well. While some font issues can be fixed by repairing permissions, more obscure issues may require you to dump the font caches and rebuild them.