I/O Error? OS X Hard Drive Failing…

2010 December 27

My Macbook (late 2008 Unibody) turned two years old a few days before Christmas. The day after it’s birthday (the only reason I know this is because I was checking where it fell in terms of warranty, but AppleCare is only one year, not two from purchase date so this was pretty irrelevant anyways) I started to suffer from a myriad of issues during use. Beachballing. Bouncing programs in the dock. Random freezes in Firefox when browsing. Connection dropouts. The works. I initially thought this was the work of an outdated program failing to play nice with the newest version of Snow Leopard (10.6.5) which I had installed days before. I began turning off plugins in Firefox and ditching programs from the startup menu to attempt to cure whatever sickness had taken over my laptop. Every reboot cycle gave me the same problem– the computer would run for about 30 seconds, but then any use and it started beachballing. Finally, it just didn’t reboot. The computer hung at the grey screen with the Apple logo and the spinning ball.

Hanging gray Apple boot screen

No peripherals (external hard drive, USB mouse, etc.) were attached so that was immediately ruled out. To attempt to diagnose the problem, I attempted to boot into safe mode. Not happening. Tried resetting the PRAM and NVRAM. Nada. Finally, the next series of steps allowed me to salvage my hard drive and let my Macbook live to see another day (minus a $700 data recovery charge).

Boot into single-user mode (sometimes called verbose mode) (hold down Control-V as soon as the Mac chime sounds after pressing the power button). You should now be in an environment that looks like this:

Single-user mode environment

At the command line type:
/sbin/fsck -fy
and press Return.

You will receive messages about the disks use and fragmentation as fsck will now go through five phases of disk utility. If you get:
disk0s3: I/O Error
then you have a problem with bad sectors on the hard drive.

Eventually, fsck will probably tell you:
Repeat the fsck process above.

Keep repeating the above process until
does not appear.
Even after this message disappears, repeat one more time. If this message doesn’t disappear, and you continue to get disk0s3: I/O Error or similar errors, it might be time to think about punting the hard drive (or visiting a data recovery specialist if you don’t have a backup).

Type reboot at the prompt.

You should be able to boot (hopefully). If you can, find an empty external hard drive. If it’s big enough (more than 2x the size of your internal drive, which most on the market nowadays should be), I highly recommend doing three things (you can partition it into 2 OS X Journaled drives for total safety, although this should work.

1.) (optional) Run Onyx maintenance scripts
2.) Clone the internal hard drive with Carbon Copy Cloner.
3.) Do a brand-new, full backup using Time Machine.

This may seem redundant (backing up your now-functioning hard drive at it’s present state twice), but there have been sporadic issues reported in the past with Time Machine backups having issues backing up drives with I/O errors. Secondly, CCC will provide you with a bootable copy of your hard drive. Why is this important? Well, if you had I/O errors during this ordeal, it’s extremely likely that your hard drive is on the way out. You may have salvaged it for now, but with 2.5″ HDD prices being under $100 these days (even their SSD cousins are coming down) you might as well drop the coin and upgrade the hard drive.

Hard drives for Macbooks are simple to replace (iFixit will walk you through the steps). You can then either restore your Macbook via Time Machine and the OS X install disk, or, more preferably, boot onto your external partition (hold down Option right after the Mac chime sounds during bootup, select external hard drive) and then clone that partition over to your newly installed hard drive using CCC (essentially the same but reverse as you did before).

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One Response leave one →
  1. 2014 July 25
    Donald Kepler permalink

    Really a very nice post. Yes this is an urgent task of cloning Mac drive before attempting any rescue steps. There are many reliable software like CCC, Stellar Drive Clone for successful Mac drive cloning. http://www.stellarclonedrive.com

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