I posted this in the MacBook section first, but I thought it'd get more attention in here, plus I messed around some more and worked out more specific details of my problem since that thread. So, I replaced my hard drive and restored the system from a Time Machine backup. It boots and all, but it seems to be missing a component. Both Safari and any app that relies on Safari crash. This affects Safari, Software Update, iTunes, iChat, iPlayer Downloader, and even Installer, among others. I do have my old hard drive in a SATA enclosure, I just mounted it and tried to run Safari from it without success, which suggests it isn't the app itself that's the problem, but one of it's core files elsewhere on the system. I made the connection to Safari because of the Console logs, which always mentioned both it and com.apple.main-thread. I could be wrong about it, but it does seem to fit. Here's the other problem, though: when I restored the system, Time Machine helpfully removed all my old backups without asking me, so if I wanted to restore the system from a backup again, I'd have to do it from a new backup which would surely have the same problem anyway. So, does anyone know what could be wrong? What file to replace? Or even just a way to check and repair my OS X install?