Disk Utility error: false alarm, or bad omen?

May 2, 2009 4:26 PM

In OS X on my iMac, Disk Utility asserts that my main, internal hard drive is "about to fail" and has been asserting this for several months. But my computer is running just fine... should I worry?

The S.M.A.R.T status is failed, and the various helpful sounding options, like First Aid or Verify, are all unclickably greyed out. Using Boot Camp and HD Tune under windows, I can see the "bad" attribute is:

ID (01) Raw Read Error Rate
Current: 11
Worst: 1
Threshold: 51
Data: 59669
Status: Failed

A different utility just names the fields slightly differently...

1, Raw Read Error Rate
Raw value: 59699
Status: FAIL
Value: 11
Worst: 1
Threshold: 51

All the ther attributes (things like "seek error rate" and "spin up time" and stuff) are normal.

But my computer is running just fine. I can't work out if this is just some freaky one-time error that happened to the hard drive once which it won't forget about, reflects an existing (if seemingly benign) state of affairs, or is a sign of impending doom. This error has been present for several months now, perhaps even from The Beginning - the iMac is only 6 - 8 months old. The Man From Apple suggested I format my entire drive but that sounds pretty tedious if I don't really need to do anything / insufficient if my hard drive is actually about to die from mechanical failure.

Obviously I'd love for you all to tell me how I can safely ignore this, and even how I might be able to disabuse Disk Utility of the notion that things are messed up. On the other hand, if you think there might be trouble ahead, then do snap me out of my complacency and I'll promise not to shoot the messenger.

posted by so_necessary to computers & internet (17 comments total)

Get the drive replaced asap. Your machine might look like it is running fine, until that one morning when you open your $collectionofvaluablefiles and it's CRC-error hell.
posted by starzero at 4:38 PM on May 2

FWIW, a 1TB drive over at Newegg is less than a hundred bucks these days- is it really worth the time that an emergency fixup will take?

(I assume you're being diligent with nightly backups to a different drive, right?)
posted by jenkinsEar at 4:41 PM on May 2

The only time you can ignore messages about hard drive failure would be when you have just successfully backed up the computer.

You have just successfully backed up the computer, right?
posted by bcwinters at 4:42 PM on May 2 [1 favorite has favorites]

Replace it immediately. I hope you are doing religious backups.
posted by BryanPayne at 4:42 PM on May 2

Back your drive up to your appropriately-sized USB or FW drive, or your buddy's, or what have you, with SuperDuper!, which only needs to be paid for to unlock its incremental-backup capabilities. Book a Genius appointment at the Apple Store and haul your Mac in for a drive replacement-- if you've got AppleCare, it should be covered.

Much easier than sitting around worrying about whether or not the drive's going to shit its pants and take your data with it.
posted by fairytale of los angeles at 4:45 PM on May 2 [1 favorite has favorites]

Backup. Now. I highly recommend Super Duper. Make a bootable clone.

Hard drives can fail, no matter how old. Sounds like yours will be under warranty though. I've been using macs for a while, but only recently had to reformat one. It was painless, and took a surprisingly short amount of time. Give it a shot. Migration assistant can even re-install all your old applications from your clone. Just a few hours.

I think the Apple guy is full of bs though. Once it fails, get them to give you a new one. The new iMacs have pretty painless HD replacement too.
posted by fontophilic at 4:47 PM on May 2

Important note I forgot, if you use a FireWire external, a bootable clone created with superduper is.. well.. bootable. It can function as your primary drive, if you can't take it into the Apple store for a few days. Plus, once you get your new internal drive, this can be your TimeMachine/backup drive.

As I understand it, Apple doesn't like using USB drives as a primary disk, (for probably only political reasons). However, Firewire enclosures/prebuilt externals will be $20 more for no good reason. But, then you get interrupted use of your computer/data, and faster speeds than USB 2.0.
posted by fontophilic at 5:00 PM on May 2

OK, thanks guys :-)

A couple of quick followups if I may:

1) Can I make a byte-for-byte "copy" of the existing hard drive and restore from that? Is that what SuperDuper is for? I use Time Machine at the moment.(I would rather keep it simple rather than have to partition, then reinstall Mac OS X, and then Windows [oh god, installing Windows, so slow...] Windows isn't backed up atm, it's just got some Steam games on it.)

2) If I just ignore the Applecare dude, go into an Apple Store and do my best pleading-yet-insistent act, do you think they'll fix it? I've been waiting for the HD to fail (so as to make my case for a replacement inarguable) but I don't want it to fail one week after the warranty runs out. Part of the laziness is the lack of a nearby Apple Store and the fact I don't drive, so it will be quite a schlep.

Thanks for the brisk wake up call so far!
posted by so_necessary at 5:09 PM on May 2

If your drive has started failing it is possible that you have already corrupted data.

Superduper creates a bootable clone. One problem with this approach is that if you have had a file go missing or corrupt, you have no other copies. Superduper alone is, for this reason, an inadequate backup approach. SD is _fantastic_ when used in conjunction with something else (time machine or crashplan).
posted by rr at 5:26 PM on May 2

ID (01) Raw Read Error Rate
Current: 11
Worst: 1
Threshold: 51
Data: 59669
Status: Failed

A different utility just names the fields slightly differently...

1, Raw Read Error Rate
Raw value: 59699
Status: FAIL
Value: 11
Worst: 1
Threshold: 51

You should have an Apple Hardware Utility disc that came with your iMac. Load that disc up, reboot the machine, and you will almost certainly see a HD error.

Either way you read it, your drive is failing. Go to the Apple Store and ask for a replacement drive. If they don't want to replace your obviously failing drive, just ask them if you can use one of the in-store macs to order a new drive from Amazon or NewEgg.
posted by b1tr0t at 6:03 PM on May 2

My daughter's iBook did this for about three weeks, then the drive failed. S.M.A.R.T status is a mechanical test. It's not a directory or data failure. I see no reason why a polite but insistent trip to the Apple Genius Bar won't bear fruit. If you go in knowing what you're talking about with your ducks in a row, they'll warranty the machine. A failed S.M.A.R.T status check should be sufficient proof that a replacement drive is warranted.

FWIW, I've had very good experiences with Applecare both via phone & via Genius Bar. You may want to call the Applecare 800 number & get a case # before you go to the Apple Store, so that dropping it off will be just a formality.
posted by Devils Rancher at 6:58 PM on May 2

This is a bit of an aside, but it should be said that S.M.A.R.T. is *not* a foolproof or even semi-reliable indicator that your drive is healthy. I work in video post-production, and have had numerous drive failures over the years, and not a single one of them gave a S.M.A.R.T. status warning before dying. Don't be led into a false sense of security by just looking at the S.M.A.R.T. status, and thinking that you're ok.

Hard drives can fail, no matter how old.

Correction. Hard drives WILL fail.

As many have already said, hard drives are so insanely cheap nowadays that they are for all intents and purposes disposable. Even if the S.M.A.R.T. failure notification is erroneous (which it most likely isn't), why bother taking a chance on losing your data? Buy another drive, use SuperDuper or CarbonCopyCloner, and be done with it. And make sure you do this before taking your iMac into the AppleStore, because Apple won't--as a general policy--back up your data or give you the "bad" drive back.

BTW, Applecare and/or the snobs at the Apple Store Genius Bar won't "fix" the drive, because as I mentioned, hard drives are basically disposable items.

I'm a rabid evangelist for the notion that you should treat hard drives as if they WILL fail at any moments notice. If you have a decent, regular backup procedure in place (Time Machine alone is indadequate, in my opinion. But it's certainly better than nothing), you generally never have to ask questions like this.
posted by melorama at 9:08 PM on May 2

needs harddrive tag
posted by humannaire at 9:45 PM on May 2

Although you said you're backing up with Time Machine and that you don't want to through the trouble of partitioning and reinstalling Windows, you should be aware of the fact that Time Machine doesn't back up your Windows partition. If you have important files on there that aren't also on the Mac side, you're going to want to back them up separately.
posted by jaffacakerhubarb at 4:08 AM on May 3

The raw read error rate tells you how much work your drive's inbuilt forward error correction logic is having to do to get you good data. It looks pretty dire at present. I would expect that once it gets even slightly more dire, the FEC will suddenly be overwhelmed and there will be bad data everywhere you look.

If you're not afraid of command line tools, and you want a 100% block-for-block backup of the entire hard disk (partition table plus all partitions, including unused blocks and deleted files), and you have reason to believe that you may strike read errors during the backup process, and you don't mind if the process is slow because it's copying every single disk block: you can't do better than Gnu ddrescue run from a bootable Linux CD. Here is a recipe.
posted by flabdablet at 8:13 AM on May 3

Thanks all, I'd mark you all best answer but instead I've arbitarily chosen a few of you. Them's the breaks, I guess. I'll report back once I've bitten the bullet.
posted by so_necessary at 9:59 PM on May 4

Man at the shop agreed with your assessment and the drive is being replaced now, hooray!
posted by so_necessary at 9:34 AM on June 9