Just happened yesterday with my Ti 500, OSX 10.2.8. I haven't resolved the problem but am following the protocol of Apple info. My Ti500 crashed after Palm device and iSync transport during startup. I got grey screen with broken apple ikon, prohibitory sign, probably kernel panic. Following Apple info titled "Prohibitory sign" I went to "Throubleshooting and resolving" and all the points #1-7 failed including trying to startup by holding shift key or command-S key. I rebuilt directory with Disk Warrior 2.1.1. Drive 10 1.1.2 shows no hardware or volume directory problems. I completed defragmentation using Drive 10. Next step is to reinstall Mac OSX according to instructions. Is my procedure correct? Do you have a hunch what the problem could be? Is there another solution? Sincerely, Milan