A vulnerability in iOS 6 and OS X 10.8 Mountain Lion can crash apps and even render them unusable if certain strings of text are rendered. The text strings can cause Messages and Safari to crash, and can cause additional errors if a Wi-Fi network is named with the text. The problem is reportedly fixed in the betas of iOS 7 and OS X 10.9 Mavericks, but we expect Apple to address it in iOS 6 and Mountain Lion updates as well. follow link
Is it a Unicode Font?
To determine if your font is Unicode-compliant, with all its characters coded and mapped correctly, choose the Font in any program (or in Font Book, set the preview area to Custom (Preview > Custom), and type Option-Shift-2.
If you get a euro character (a sort of uppercase C with two horizontal lines through its midsection), it's 99.9 percent certain the font is Unicode-compliant. If you get a graphic character that's gray rounded-rectangle frame with a euro character inside it, the font is definitely not Unicode-compliant. (The fact that the image has a euro sign in it is only coincidental: it's the image used for any missing currency sign.)
This assumes that you're using U.S. input keyboard, which is a little ironic when the euro symbol is the test. With the British keyboard, for instance, Option-2 produces the euro symbol if it's part of the font.
Text Display Bug Can Render Apps Unusable