I’ve got TechTools Pro, acquired via one of those mac software bundles a while back, and when giving it a run through a couple of weeks ago I must have let it delete something that shouldn’t have been deleted….not sure why it let me do that in the first place without a warning. I sort of recall doing a “preferences’ style cleanse and deleting one or two which came back to haunt me as when I used Onyx to verify the start up Disk it got half way through and gave me an error message advising that the Start Up Disk needed repairing……a bit worrying really.
I fired up Disk Utility (in your Utilities folder in the Applications folder) with the aim of verifying then repairing the Start Up Disk but the mac OS could not do it, again giving me the same error message and advising me to insert the original Snow Leopard install disk and doing it from there. That turned out to be fairly easy, I think I held down C while the laptop was starting up to boot from the installer DVD then selected Utilities, went into Disk Utility and it repaired the start up disk for me. I then shut down, rebooted in normal mode and everything was fine.
Things like that are a good reminder though to carry out some routine maintenance, most of which can be done with the Disk Utility (located in Applications-Utilities folder). Repairing disk permissions every now and again is also a good idea. Onyx can do all that and a lot more too and being freeware, is worth checking out.