PCs

How to diagnose a failing Mac hard disk

Erik Eckel shares some tips for diagnosing and recovering a failing Mac hard disk.

Potentially the greatest technology stress and heartbreak results from failed hard drives, a risk from which Mac users certainly aren't immune. The more business data or even personal information a user maintains on a Mac, the more important a Time Machine and even automated offsite backup (such as a Carbonite or Mozy) becomes. When hard disk trouble is suspected, it's critical that troubleshooting begin quickly.

If the Mac will boot

When the Mac still starts up properly, the best first step to take is to make a complete backup of the system's data. Once a full backup is confirmed, troubleshooting can begin.

Obviously, if audible clicks can be heard, that's a sign the hard disk's head may be striking the platters. In such cases it's likely best to simply replace the drive. At a minimum diagnostic tests should be run on the disk. The Mac's native Disk Utility application can help determine whether a system's hard drive is encountering trouble. While Disk Utility doesn't fix physically failing disks, it can help speed diagnosis.

  1. Using Mac OS X Lion, open Disk Utility (found in Applications\Utilities).
  2. Select the Mac's system disk and click the Verify Disk or Repair Disk button found on the First Aid tab.

The utility will check the hard disk. Typically the utility should respond that the volume checked "appears" to be OK. If you receive an error message instead, or warnings indicating damage, the disk should likely be replaced (additional tests could be run on the disk using a utility such as DiskWarrior or TechTool Pro, which can further diagnose bad blocks and report detailed SMART status disk health information).

I believe that, once bad blocks appear, businesses are best served replacing the failing drive. Some, however, choose to continue using the disk, hoping that the damage is limited to specific blocks or sectors.

If a connected disk doesn't appear within Drive Utility or the Mac's System Information report (reached by clicking the Apple icon from the menu bar and selecting About This Mac | More Info | System Report), that's a probable sign the disk is experiencing difficulty.

If the Mac won't start up

When faced with a Mac disk issue that prevents proper startup, I often first check to determine the system's warranty coverage with Apple. If the system is covered by Apple's initial warranty or an extended AppleCare Protection Plan, I ask the client or user whether they wish to let Apple perform the diagnosis and repair to help lower the repair cost. But if the system's disk is out of warranty I usually remove the drive from the failing system and connect it to a test system to determine whether I can run diagnostic tests on the slaved drive.

Another option available to Mac users whose systems possess a Lion recovery partition (such as is found on many new models) is to attempt booting using Recovery Mode. Enter Recovery Mode on recovery partition-equipped systems by holding the Command and R keys during startup. The Mac OS X Utilities window should appear, from which you can run the Disk Utility to determine if the application can verify or repair disk issues.

Another option is to boot from the Mac Install DVD. To do so, install the DVD, start the Mac while depressing the C key and select Disk Utility from the resulting Mac OS X Utilities window.

About

Erik Eckel owns and operates two technology companies. As a managing partner with Louisville Geek, he works daily as an IT consultant to assist small businesses in overcoming technology challenges and maximizing IT investments. He is also president o...

11 comments
JackR10
JackR10

I found the following list of hard drive and system testing tools for Macs over on MacRumors. I hope it's OK to post the link here. It isn't an ad, it just lists most of the better known tools ranging from Disk Utility, to open source, plus a myriad of commercial tools. Here's the link:


http://forums.macrumors.com/showthread.php?t=1544280


Enjoy!

ManchesterDataRec
ManchesterDataRec

We've had a lot of customers telling us that they thought that Apple Mac computers don't fail. They do. The defective Seagate HDDs in the 2006/7 MacBook range were notable, and then there were some Hitachi HDDs which would also over heat. More general problems we see the SATA I/O chips fail on the motherboard too. Then there is the corruption of the HFS+ filesystem which can lead to quite a complicated apple mac data recovery. Remember using disk utility or Disk Warrior on a failing HDD or SSD can make matters quite a bit worse.

DaizyTech
DaizyTech

Use Drive Status utility of Stellar Drive ToolBox tool to find out problems of Mac hard drive. I would like to suggest you to check your Mac drive health regularly to find out bad blocks and memory issues

JackR10
JackR10

I know that sounds stupid, but there seem to be some bogus sites out there that tell people how to "correct" problems, particularly when the system is having problems booting, and their advice isn't sage, it's probably criminal. I came across one of these once and the writer gave explicit instructions how to make changes to some critical permissions and files in the root OS, and if you do so, he claimed it would fix your problems. I didn't believe it so I cloned an OS onto a FireWire drive and it literally rendered a perfectly good operating system totally useless. BUYER BEWARE. I knew enough to be wary of this sort of thing, but I bet a lot of others aren't.

Bob OS X
Bob OS X

We use a product named "Scannerz" for disk and system troubleshooting. It can find disk surface problems and help isolate bad cables, etc. Personally I think it's a bit for the more technically oriented, but I guess a fair number of people are using it. A word about USB thumb drives with OSes installed on them. TAKE THEM OUT OR WHEN NOT IN USE DISABLE SPOTLIGHT INDEXING ON THEM. I made that mistake with one that was 32G. I put Snow Leopard on it as an emergency boot flash drive, and because there was so much space left over I started using it to transfer files on it. One day I went to write to my trusty thumb drive and it was rendered read-only. I found out that Spotlight was continually updating the indices on it, and it depleted the write cycles on it. Remember an thumb drive is not an SSD - it's not intended to handle continual reading and writing. As an FYI, I think it was installed in the USB slot for about a month continually (more or less) fot that to occur.

BALTHOR
BALTHOR

If there's anything ever wrong with a computer it's a virus.Nobody ever typed the word 'error' when writing for computers.Erase the drive and reinstall.

egarbeil
egarbeil

2 words - Disk Warrior P.S Back up early and often

macmadman
macmadman

I created a bootable USB stick and have loaded all my utility software onto it. I then boot the Macintosh from that by holding down the Option key during startup and selecting the USB drive as the startup drive. This gives me more portability than a laptop, but perhaps not as much capability. I've used this for some time, and it works well in my situation.

WasabiMac
WasabiMac

If the system is really flaky but kind of works, booting the dying machine into target disk mode is handy as well. It lets you connect the ill machine to a healthy one to diagnose or recover data without having to crack the case. If you have a utility laptop loaded with your software tools, it can save time and prevents warranty issues you might run into if you open the case. Apple's instructions are below: http://support.apple.com/kb/ht1661

DJThumper
DJThumper

I too have made bootable thumb drives. Mine are actually the install DVD with the OS X drive utilities. I just recently used it for a failed drive.

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