Originally Posted by yakers
Have had apple computers at home since, well, forever, Apple2e, PCs at work. I am faced with the first problem I cannot solve myself, I am getting a kernel panic when I try to boot up from my main (external) hard disk. I have three backups but when I erase & restore from Time Machine I have the same problem. I know it's software not hardware as I have an external HD with an older system that boots fine, as well as booting from install DVDs. Disk Utility and Disk Warrior don't find any hardware or software problems. Made an appointment with the Genius Bar for Monday but wondering if any folks here have any insight to offer
Hitting the Genius Bar is a good idea. This sort of problem can take a bit of detective work to isolate.
1) The machine boots from an older system on an external drive, and from a DVD, so the processor and main memory are almost certainly OK. (The DVD boot does some extra diagnostic checks as a sanity check on the machine.)
2) If the Time Machine restore erased and reloaded the internal disk, then formatting errors are not an issue, and a low level hardware disk flaw is very unlikely as that would produce a "Disk I/O Error" during the restoration process. You could still get a panic if a disk defect were in just the wrong spot and was marginal, not a solid, hard failure yet.
3) The fact that you get the kernel panic after restoring points to a software issue. The most likely candidate is a third party device driver or low level user space software (like the PGP disk encryption package) that is not compatible with the installed operating system software.
Without knowing the exact system profile (hardware, software, device drivers, and connected gadgets) is is very difficult to track down this sort of problem.
More Info: OS X: About kernel panics