The volume Macintosh HD was found corrupt and needs to be repaired

Question

My Macbook Air (first gen) is very slow to start up probably because of the volume Macintosh HD is corrupt.

It takes infinity time to startup in normal mode and it takes about 1 hour to start up in safe mode.

In safe mode, I tried to run the "Disk Utility" and to execute "Repair Disk Permission" and "Repair Disk" without success.

Here is the logout (1) of "Disk Utility". I tried to repair disk doing boot from external DVD but it takes infinity time to load programs from dvd (I did wait for about 3 hours without any result). I tried also to mount a USB pen in safe mode to buck-up data without success.

Any idea?

Thanks, Antonio

(1)

Verify permissions for “Macintosh HD”
Warning: SUID file "System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/MacOS/ARDAgent" has been modified and will not be repaired.

Permissions verification complete

Repairing permissions for “Macintosh HD”
Warning: SUID file "System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/MacOS/ARDAgent" has been modified and will not be repaired.

Permissions repair complete

Verifying volume “Macintosh HD”
Performing live verification.
Checking Journaled 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.
Invalid volume file count
(It should be 675058 instead of 675059)
Invalid volume directory count
(It should be 189754 instead of 189753)
The volume Macintosh HD was found corrupt and needs to be repaired.
Error: This disk needs to be repaired. Start up your computer with another disk (such as your Mac OS X installation disc), and then use Disk Utility to repair this disk.

Answer 1

At this point, I think your safest bet is to boot to the Mac OS X installation environment and transfer your information to an external drive, then do a clean installation. If you have a Time Machine backup, you can use it to restore your operating system without the file system corruption.

Get into the installation environment on a MacBook Air, you need either a USB DVD drive or a second computer to host the installation DVD and use Remote Install. Full instructions are listed in Apple's knowledge base under "Reinstalling software using Remote Install Mac OS X".

Answer 2

Do you have a traditional hard disk drive or an SSD? If it's a traditional hard drive you probably have a bad block that needs to get written to so the drive can lock it out. See if you see generic or "undefined" disk I/O errors in /var/log/kernel.log or /var/log/system.log.

Boot from another drive and back up what you can if you don't already have a good backup, then boot from a Mac OS X Installer DVD and format your entire hard drive with "Zero Out Data" to ensure every block gets written to, so your disk gets a chance to lock out the bad blocks.

Then you can restore from your backup or do a clean install.

The hard drive engineers I know say that once a hard drive gets a bad block, it's highly likely to have a lot more bad blocks soon. It's basically "circling the drain"; about to die completely. So don't trust it much. Replace it as soon as you can, and make sure to use Time Machine religiously until then.

If you need an efficient way to back up whatever data you can from a failing drive, and you're Unix-savvy, I recommend GNU ddrescue (not to be confused with the very similarly named dd_rescue, which is not from GNU). You can install ddrescue via MacPorts, and probably via Fink and Homebrew as well. It's a bit of a pain to figure out how to use the first time, but once you get past the learning curve, it works pretty well. Tip: Use it with a log file. It does a lot of neat tricks to copy what it can from a dying drive while finding and avoiding the bad blocks. If you tell it to back up your drive to a file on a (much larger external) drive, just name that file ending with .dmg and Disk Utility will be able to mount it like a disk image later for when you want to restore it to a new drive.