After I updated my Mac to IOS X Yosemite, I opened Illustrator CS5 and my font list no longer displays the fonts available. The type box expanded looks like one big gray rectangle. When I scroll over the font names they are there and I can click on/use them. I just cannot preview them.
This should be in the regular forum but the answer is to go to System Preferences/Accessibility and then check the box that says Reduce Transparency so it is on.