How do I repair a disk that's OK?

Question

I'm trying to do a remote install, and it fails, telling me that the Macintosh HD needs to be repaired. But when I verify the HD, Disk Utility tells me that the disk is OK. How do I repair a disk that's OK?
Here's the context. I want to install Lion on a MacBook Pro (“MBP”) that’s currently running Leopard. Apple says to install Snow Leopard and then get Lion from the App Store. So I bought a Snow Leopard install disk and thereby discovered that my MBP’s SuperDrive is no longer working. Had I known, I could instead have bought Lion on a flash drive, but I’ve already paid for the install disk. I’ve also got an eMac running Leopard, but I don’t have a FireWire 6-pin to 6-pin cable, so can’t use target disk mode. So I’m trying a remote install.
To remote install, I put the DVD into the eMac and turn on DVD Sharing. Back on the MBP, I use Terminal to enable ODS:
$ defaults write com.apple.NetworkBrowser EnableODiskBrowsing -bool true
$ defaults write com.apple.NetworkBrowser ODSSupported -bool true
and reboot, and now I get a Remote Disc in the MBP’s Finder Sidebar Devices. I select the Remote Disc and the eMac shows up in the Finder window. I double click the eMac icon, and the remote Mac OS X Install DVD opens in the Finder window. I double click the installer and it starts running, so I’ve succeeded in starting a remote install. The problem is that the installer quickly fails with this message:
The disk “Macintosh HD” needs to be repaired.
Go to the computer with the Mac OS X Install DVD, open Remote Install Mac OS X (located in the Utilities folder in the Applications folder) and follow the onscreen instructions for restarting your computer using the DVD.
When the Mac OS X Installer opens, follow the onscreen instructions to install Mac OS X. During installation, the Installer repairs the disk automatically.
I think what it’s suggesting is that I boot my MBP from the remote disk. (Right?) I think that won’t work for me because I’ve got a MacBook Pro rather than a MacBook Air or Mac Mini, which are the only types that can boot from a remote disk. (Right?) Instead I thought I’d do whatever repair is necessary to the MBP’s Macintosh HD and then try the remote install again. So I ran Disk Utility on the MBP to verify the Macintosh HD, but it succeeds with “The volume Macintosh HD appears to be OK.”
I can’t remote install until the disk is repaired. But how can I repair a non-existent problem?

Answer 1

Repair the Hard Drive and Permissions
Boot from your Snow Leopard Installer disc. After the installer loads select your language and click on the Continue button. When the menu bar appears select Disk Utility from the Utilities menu. After DU loads select your hard drive entry (mfgr.'s ID and drive size) from the the left side list.  In the DU status area you will see an entry for the S.M.A.R.T. status of the hard drive.  If it does not say "Verified" then the hard drive is failing or failed. (SMART status is not reported on external Firewire or USB drives.) If the drive is "Verified" then select your OS X volume from the list on the left (sub-entry below the drive entry,) click on the First Aid tab, then click on the Repair Disk button. If DU reports any errors that have been fixed, then re-run Repair Disk until no errors are reported. If no errors are reported click on the Repair Permissions button. Wait until the operation completes, then quit DU and the installer.
If DU reports errors it cannot fix, then you will need Disk Warrior and/or Tech Tool Pro to repair the drive. If you don't have either of them or if neither of them can fix the drive, then you will need to reformat the drive and reinstall OS X.
Booting From An OS X Installer Disc
  1. Insert OS X Installer Disc into the optical drive.
  2. Restart the computer.
  3. Immediately after the chime press and hold down the "C" key.
  4. Release the key when the spinning gear below the dark gray Apple
      logo appears.
  5. Wait for installer to finish loading.