Kernel Panic:
When OS X goes "pop!"
By Paul Needler
Posted on July 9, 2003, with the author's permission.
The evolution of OS X has brought with it many new features to advance our computing power. It has also brought with it many new error codes, in the rare event that something does go wrong. One of these new codes is something that does not pop up very often at all. However, when it does it should be paid attention to. Kernel Panic: Something you might see if someone drops their popcorn? No, not at all.
How to identify a Kernel Panic
Kernel Panic is a result of the computer entering a state other than that of normal operation. More on that point later in this article. More times than not a Kernel Panic will occur on startup of the OS. You may occasionally get a Kernel Panic during system operation or while using an application.
The images below show you what a Kernel Panic looks like. This first one is typical of OS X 10.1.x, and the second is the much more polite, less-alarming look of a kernel panic in OS X 10.2.x:
If you get either of these images on your screen, OS X has had a Kernel Panic.
What is a Kernel Panic, and why does it happen?
A Kernel Panic is a type of error that takes place when the main part of the operating system, known as the kernel, receives an instruction that it does not understand or cannot handle, the way it expects to. Kernel Panic can also happen when the operating system fails to recover from another error. Less common, is a Kernel Panic resulting from damaged or incompatible software. Defective or incompatible hardware can also cause a Kernel Panic, but even less likely than software.
Let’s take this out of technical terms for a moment. Suppose that you are a master of the English language. You know even the most obscure words and their meanings. Further to this, you are able to understand information from the most elaborately written books. Also, you can understand the variations of English as it changes through the different regions of the world. Now, suppose some joker gives you a sentence that has English words in it, but does not form a complete thought. Like, "Tuesday grass vacuum writes carpet salamander". You become confused. This is comparable to a kernel panic by failure of understanding. Worse off, you get a book from the library, only to find that the English has been written backwards. "Panic to you cause certainly would this" This would certainly cause you to panic. This is comparable to a kernel panic by damaged software. Now, what about complete panic? Suppose that you have an exam coming up and you have to study from a book. Well, you get the book you need from the librarian, only to find that most of the pages have been torn out. Feeling stressed out yet? This is comparable to a kernel panic by defective hardware.
Did I do anything to cause this?
This is the first question I get from clients when things go wrong. Well, here are some of the things that can cause a Kernel Panic, according to Apple KnowledgeBase support documents:
Renaming or relocating system-installed folders may lead to a startup issue or kernel panic. Do not relocate system-installed folders (such as Applications, System, or Library) while started up from Mac OS 9, or logged in to Mac OS X as the root user. If you have moved or renamed system-installed folders, you should return them to their original location or rename them using their original names. When booted from OS 9, you may get to see some of these invisible OS X files, like mach_kernel, automount, Library. You should not touch these files at all.
Modifying the privileges of Mac OS X system files may contribute to a kernel panic. Do not change privileges of any of the system files.
As mentioned earlier, hardware can be associated with kernel panic. This can include defective Apple hardware, and defective or incompatible 3rd party hardware (add-on cards like video cards, for example). Also, 3rd party software can have the same effect if it is defective or incompatible with OS X.
Make it stop!
If you take the precautions mentioned above in regards to not moving or changing system files, you should run pretty smoothly. However, if you still get Kernel Panics, you should follow this short checklist:
- verify the compatibility of 3rd party hardware and software with OS X
- remove any 3rd party cards or devices from your computer
- reinstall any 3rd party software that produces a Kernel Panic when launched
- take a note of when the Kernel Panic takes place (startup or otherwise)
- take note of what the Kernel Panic message says, for reference, and restart your computer
- if the Kernel Panics persist, call Loop for further troubleshooting
Remember, a Kernel Panic is the way that OS X lets you know that it cannot understand something. So, don’t you panic. One of you has to understand what’s going on.
Happy Mac!
Paul Needler is a National Service Manager at Loop
Enterprise Inc.
Use British spelling in your searches