Disk utility message...what does it mean?

Question

Hello all
Been having a few problems with my mac book pro since iphoto (bane of my existance) crashed. Problems with iphoto are ongoing discussion on this forum - but I seemed to have concurrent issue with the computer - when I restart the dock loses word and a couple of other things, and a large question mark appears, claiming to be imovie (when infact Imovie is next door). It also no longer seems to be 'retrieving space in my file vault' when I shut down.
I ran disk utility and had a series of repaired permissions, then ran verify disk and got the following:
Verifying volume “Macintosh HD”
Checking HFS Plus volume.
Checking Extents Overflow file.
Checking Catalog file.
Checking multi-linked files.
Checking Catalog hierarchy.
Checking Extended Attributes file.
Checking volume bitmap.
Checking volume information.
Volume Header needs minor repair
d.",1)
Macintosh HD
Error: The underlying task reported failure on exit
1 HFS volume checked
Volume needs repair
Which clearly implies the volume needs repair---wasn't running disk utility off the dvd, so no repair option was visible. (The original disk is at home some distance away) Can anyone tell me if the above implies major surgery required, hence a shop, or whether I might be able to deal with it from the original dvd, once I head home in the new year?
Thanks
Vx

Answer 1

Vx,
No, a disk error is just that, and not generally caused by anything you may have done (unless you are in the habit of forcing shutdowns while copying or otherwise writing files, etc.). Likewise, it won't be caused by "bad" files. Actually, the opposite is true; disk errors create bad/corrupt files.
More specifically, a disk error occurs when the "index" that describes each and every file on your hard drive, and the actual physical locations on disk of the data associated with those files, fails in some way. This can be caused by some random write error at a critical point in time, or it can less frequently be caused by a true "dead spot" on the surface of the drive platter (a "bad block" or sector. You only need worry about this if the error recurs after a format).
I will second Sig's suggestion that you attempt to repair the error using Disk Utility's command line interface, while booted into "Single User Mode." Please follow his instructions for doing so, if you want to make this attempt. I will state, however, that I am pretty certain that in any case where the "Verify" function fails with the error you have reported, Disk Utility probably won't be able to make the repairs.
If this becomes an emergency, you can use one of the more powerful and flexible third-party utilities, such as Diskwarrior. They can be pretty pricey, but they can often make repairs when Disk Utility cannot.
Once you have erased that hard drive and reinstalled OS X, you can indeed copy back or otherwise re-import all of your backed up data. If at all possible, do try to make another backup copy of anything and everything in your current HOME folder before erasing that drive.
Scott