Fontbook not installing fonts

Hi, when I doubble click on a .ttf it opens in fontbook, but when I press install, it dissapears and nothing happens.

The only way it will behave is if I restart the computer, very frustrating.

Any ideas?

Cheers.

Did you check to see if the fonts were being installed to your user fonts folder?

MacIntosh HD/Users/your user name/Library/Fonts/

yes, its in there and still not showing up in illustrator?

Then the fonts may not be compatible with Illustrator. The same problem occurs with certain fonts and Microsoft Office. I have several font sets that I can use in TextEdit and other apps but MS Office refuses to "see" them. Illustrator may be just as fussy.