About "You need to restart your computer" (kernel panic) messages
Summary
UNIX-style operating systems (such as Mac OS X, Mac OS X Server, AIX, and A/UX) may experience a type of issue called a "kernel panic," which may provide information useful for software developers or troubleshooting. In Mac OS X 10.2 or later, the message that appears states "You need to restart your computer. Hold the Power button for several seconds or press the Restart button."
Tip: Update to the latest versions of Mac OS X to avoid certain potential kernel panic situations.
Products Affected
Mac OS X 10.4, Mac OS X 10.3, Mac OS X 10.2, Mac OS X 10.1, Mac OS X 10.0, Mac OS X 10.5
Depending on which version of Mac OS X you are using, a kernel panic's alert message appears in one of the following ways.
Mac OS X 10.2, 10.3 or later
Sample kernel panic message in Mac OS X 10.3 or later
Sample kernel panic message in Mac OS X 10.2 through 10.2.8
Mac OS X 10.2 and later include automatic kernel panic logging, so you may not see any visual indication of a kernel panic. You can check kernel panic logs (located in /Library/Logs/PanicReporter) any time that you must force restart your computer, using either the power button or the Control-Command-Power key combination. The kernel panic text is added to the log the next time you restart the computer, assuming that you have not reset PRAM at the same time (the kernel panic text is stored in PRAM until you restart).
Mac OS X 10.0 through 10.1.5
If this happens in either Mac OS X or Mac OS X Server version 10.0 to 10.1.5, white text on a black background is drawn on top of the last video image on the monitor before the issue occurred. The text of a panic m essage might contain something like this:
- "Unresolved kernel trap(cpu 0): 0x300 Data access DSISR=0x40000000 DAR=0x0000006c PC=0x06d77510 MSR=0x00009030
generating stack backtrace prior to panic:
backtrace: 0x06d77510 0x0002a1fa 0009d1ef 00099440 012f4102 kernel modules in backtrace: com.apple.filesystems.cddafs(1.0) @ 06d75000
Memory Access Exception(1,0,0) Waiting for remote debugger connection"
Sample kernel panic shown in Mac OS X 10.0 to 10.1.5
What's included in a kernel panic message or log?
Kernel panics generate information that may aid developers in the investigation of a software issue. It is useful to record any information that appears during a kernel panic, in addition to how the computer was being used when the kernel panic happened--was the computer starting up, shutting down, or performing a particular task?
Recording kernel panic information
In Mac OS X 10.2 and later, the kernel panic text is logged automatically for you as described above. In Mac OS X 10.0 to 10.1.5, the computer is in a non-responsive state during a kernel panic, so you can't take a screen shot. But you can type the information on another computer or write it out by hand.
Troubleshooting
If you are experiencing a recurring panic issue and don't know how to troubleshoot it, see "Isolating issues in Mac OS X".
Additional Information
A "kernel panic" may occur when the core (kernel) of an operating system receives an instruction in an unexpected format, or that it does not handle properly. A kernel panic may also occur when the operating system is not able to recover from a different type of issue. A kernel panic can be caused by damaged or incompatible software or, more rarely, damaged or incompatible hardware.