I don't 'effin believe it.

I have two backup external HDDs attached to my Mac. Drive 0ne receives the hourly backup from Apple's Time Machine, drive two clones my drive every night (so I can boot from it in an emergency).

Yesterday I noticed drive 1 had was not mounted and I could not get it to mount. (Power light on cables checked) I took it out and it would not mount to my laptop either. It was making a tick tick tick noise.

Then

I looked and noticed that drive 2 that was their a minute ago was no longer mounted. I figured that I must have unplugged the cable as I was messing about with drive 1. I checked everything but it still would not mount. As per drive 1 the light was on and it was going tick tick tick. It would not mount to my lappy either.


A spare drive I have mounts on both computers just fine. I am backing up again to it as I type this.

What is going on? Any ideas?




p.s. For you Mac users Disk Utility does not see either drive.

Does OSX (Or whatever your laptop runs as well) have dmesg installed? If so does that give any interesting output when you plug the HDD in? The drive that's ticking sounds as though it might have just bitten the dust. :-/

There is probably an equivalent to dmesg what does it do?

Both drives are ticking

It does sound suspiciously like both drives have died CC.
Has there been a power cut or anything like that recently?
Did you buy both drives at the same time?

Oh Dear Is there a doctor in the house ?

That is what I thought.

They are protected by a UPS so it is not a power cut. Both drives are of similar age.

I can only assume that one died and the other was close to it. Moving it around must have pushed it over the edge.

I wonder if I can re use the enclosures? One has an expensive triple interface.

If they were on a UPS then it's unlikely to have been a surge/spike or cut.
Sounds like you've just been monumentally unlucky.
How old are the drives? They may still be in the manufacturers warranty if they are less than 2/3 years old.

The only way to test the enclosures is to try a new drive I suppose. Not what you want really.

There is a thought. I will look into that.

It may just be the PSUs have died. Are the unusually hot or cold?

As I think you are well aware, the ticking you describe is ominous. It usually means the heads are no longer able to track over the disk accurately.



How old were the drives? I always try to replace them at 3 years which is the usual guarantee these days. Anything over 5 years is pushing your luck, unless they're rarely used and kept in a secure cool location.

I know it's not your situation, but it's very common for 2 drives in a RAID mirror to fail at almost the same time. They're often identical twins and subjected to identical lives, so it's not surprising if they meet identical fates.

Moving a drive while it is powered on is a huge big NO! Just don't do it. Ever. The heads are flying just a few atoms width above a platter moving at 150mph. Twisting a drive at any angle away from that in which it is spinning can make the heads crash. Laptop drives are designed to be more resilient to this at the expense of performance, but 3.5" desktop drives do not expect to be shaken around even slightly. My netbook even has an accelerometer which rapidly parks the heads if it detects dangerous motion, but desktop drives do not.

The drives in your enclosure are probably quite standard. Replacing them is most commonly a matter of a few screws, and being sure to choose a compatible unit. Once you've removed the old drive, identifying it should be easy - especially when you're on a computer forum full of hard drive geeks!

You may find you can recover some data by balancing the drives at a certain angle. I was quite amazed to recover nearly 500GB from a dead drive in this way; I guess it's a question of exactly what failed. In my case I think maybe it was the return spring, so gravity was able to assist!


This is niggling me. Even if the drive is badly damaged mechanically, usually if the electronics are not fried then you can still detect it when it's plugged in

When I get chance I will have to dig out the receipts. I think they are about two to three years old. They are in a position where there is not a lot of air circulating so they must get pretty warm so this may explain the shorter life.

I now have a new Time Machine backup, so I can breath again.

Now to clone my internal drive overnight so that once again I have two backups. I wonder if I should invest in a Drobo?

I've had some luck in the past with Drive Genius (disk repair utility) and Data Rescue II (data recovery utility, now at version 3), which both managed to retrive at least some data from a colleague's laptop drive which Disk Utility failed to recognise. Both of the above have a free trial version available but the trial is limited to restoring only one file - but at least this would stop you wasting money on software that might not do the job. See here

However, if it's a hardware fault, which is sounds like it is, then no software is likely to recover the data. If it's valuable data, then try a specialist data recover company, but I suspect this will be very expensive - if it's just for a Time Machine backup, then just get a new drive as soon as possible and chalk it up to bad luck.

I've also heard good things about DiskWarrior - which focuses on rebuilding the directory on the hard drive, replacing it with the one that's possibly damaged. The clicking sound is a sign that's it's probably not a software problem though.

Thanks Steve, however I have lost no data. It is just that my belt and braces both snapped in the same week. My trousers did not fall down. i.e. I have lost two backups but the internal drive is still sound.

You are smarter than your average cat


IT rooms are chilly for a good reason. For every degree above about 30C (depending on design) the life expectancy roughly halves.

As a smart cat, I'm sure you will learn from this.