Leopard introduced the concept of protected fonts, making it virtually impossible to disable the require system fonts. Follow the instructions in our 'Undoing Font Book' FAQ to resolve any issues that may have been caused by using Font Book incorrectly. Likewise, if you incorrectly resolved duplicate fonts, you may have disabled key fonts. If you disabled fonts with Font Book, particularly System fonts, re-enable them.If you recently installed new fonts, remove them.When multiple applications quit unexpectedly or fail to launch, it is often a font problem. Perform the troubleshooting steps below in the order specified. This FAQ, derived from information in our Troubleshooting Mac® OS X series of e-books, can often resolve situations where multiple applications quit unexpectedly or fail to launch. In addition to the reasons cited in the articles above, we would add the following in cases where multiple applications quit unexpectedly or fail to launch. 'Relaunching an application after it unexpectedly quits.' The following AppleCare® Knowledge Base documents from Mac Help provide some assistance in troubleshooting cases when a given application quits unexpectedly or fails to launch: Mac OS X version: Multiple applications quit unexpectedly or fail to launch
