. Startup Problems Not every problem you encounter is related to running applications. Sometimes trouble strikes before you even get that far. The following are examples. | . Startup Problems Not every problem you encounter is related to running applications. Sometimes trouble strikes before you even get that far. The following are examples. . Kernel Panic When you see the cheerful multilingual dialog box shown in Figure B-2 you ve got yourself akernel panic a Unix nervous breakdown. In such situations user panic might be the more applicable term but that s programmers for you. If you experience a kernel panic it s almost always the result of a hardwareglitch most often a bad memory RAM board but possibly an accelerator card graphics card SCSI gadget or USB hub that Mac OS X doesn t like. A poorly seated AirPort card can bring on a kernel panic too and so can a bad USB or FireWire cable. If simply restarting the machine doesn t help detach every shred of gear that didn t come from Apple. Restore these components to the Mac one at a time until you find out which one was causing Mac OS X s bad hair day. If you re able to pinpoint the culprit seek its manufacturer or its Web site on a quest for updated drivers or at least try to find out for sure whether the add-on is compatible with Mac OS X. Tip This advice goes for your Macintosh itself. Apple periodically updates the Mac s own drivers in the form of a firmware update. You download these updates from the Support area of Apple s Web site if indeed Mac OS X s own Software Update mechanism doesn t alert you to their existence . There s one other cause for kernel panics by the way and that s moving renaming or changing the access permissions for Mac OS X s essential system files and folders the Applications or System folder for example. See Chapter 12 for more on permissions. This cause isn t even worth mentioning of course because nobody would be that foolish. . Safe Mode Safe Boot In times of troubleshooting Mac OS 9 fans used to press the Shift key at startup to turn off the extensions. Windows fans press an F-key to start up in Safe Mode. Either way the idea is the same .