Sign in with
Sign up | Sign in
Your question

Corrupted external hard drive repair

Last response: in General UK & Ireland Discussions
July 30, 2012 9:50:42 AM

OK, Can't see the external hard drive, its connect by USB, it starts up and makes all the right noises. The computer makes the noise that it is has something plugged in. but no sign the only sign is in the device manager no letters attached and can't do that either
July 30, 2012 6:15:02 PM

Hello and welcome to Tom's Hardware Forums.

If an external drive either has no drive letter or has lost it for some reason, it can't show in My Computer but it should show up in Control Panel>Administrative Tools>Computer Management>Disk Management. If it's new, initialise and format it then assign a drive letter if you want it to have a fixed one, then it will show in My Computer.

If it's an existing drive with data on it, give it a letter then see if it appears in My Computer. If the files are not showing, use some recovery software - Recuva from the CCleaner people at is a useful free one to start with.

July 30, 2012 6:42:01 PM

Thank you for that reply. But I am well passed that stage. I cannot do anything to the drive in Disk management. other than possible reformat it and there is loads of data on it.. I am at the stage where I need to ghost the files off the system some how, I remember reading about how to do it and then had to mov and I don't have the site for it now... I believe when a computer reads an external hard drive it must have header to read first and at the moment it can't see them therefore I can't get passed this.
Related resources
July 30, 2012 7:30:36 PM

To add to that it says that the disk is not ready when i TRIED to initilized it.
July 30, 2012 7:45:59 PM

I can now see it in device manager as a USB DEVICE although it cannot not be accessed.
July 31, 2012 7:24:15 AM

It could be worth using a Live CD of a Linux OS in case that can manage to mount the disk. In extreme circumstances when all else has failed, I have carried out a quick format to get out of the problem because at least it makes the disk visible. From then on it's down to recovery software which usually produces a high percentage result.

It sounds extreme but if there are no choices left but to lose the data, it's worth a shot.

July 31, 2012 11:50:48 AM

Kernel for Windows Recovery is a professional user centric data recovery tool that successfully recovers lost and inaccessible data from damaged local hard drive or other storage media. It effectively recovers all files and folders inaccessible due to MBR loss or partition deletion and MFT damage issues. The tool supports SATA, PEN, ZIP, IDE, EIDE, SCSI, USB drives and supports FAT16, FAT32, NTFS and NTFS5 file systems.
For more information -
July 31, 2012 6:04:50 PM

Oh dear - someone's smart ad bot has sniffed out the words data recovery and brought a dubious product out of the woodwork.

I usually recommend Piriform's Recuva from (the CCleaner people) and Restoration 2514 - be careful where you download that and make sure it's all you get. They are both free, and not $49 with a worthless evaluation version, so I suggest using them first.

September 16, 2012 8:02:47 AM

Saga Lout said:

If the files are not showing, use some recovery software - Recuva from the CCleaner people at is a useful free one to start with.

Or, open command prompt (under Start > All Programs > Accessories) right-click on Command Prompt and select Run as administrator. In cmd window that appeares type:
chkdsk x: /f
(where x = drive letter associated with your external hard drive, and before x: and after x: there is a space)
and press Enter.
Command chkdsk (check disk) would correct errors and fix the problem.
September 16, 2012 7:29:21 PM

If he hasn't fixed it by now, I doubt he's bothered by another suggestion which, by the way, is incorrect. The /f switch works within Windows but in Command Prompt you need to change it to /r for the best effect.

September 17, 2012 2:20:40 AM

Saga Lout said:

If he hasn't fixed it by now, I doubt he's bothered by another suggestion which, by the way, is incorrect. The /f switch works within Windows but in Command Prompt you need to change it to /r for the best effect.

It is not incorrect, sorry. As you probably know, DOS command (within Command Prompt, of course) chkdsk x: /f fixes errors on the disk, while syntax with parameter /r locates bad sectors and recovers readable information on the disk. Therefore, first step would be /f to fix errors which usually solves the problem and reduces the amount of time required to run chkdsk command. For more information on chkdsk please read this:
September 17, 2012 6:23:50 AM

We seem to agree - the /r switch does the whole job properly and /f doesn't.

September 17, 2012 6:59:12 AM

Absolutely. In my experience, the first step is /f (as that usually fix the problem with inaccessible disk), and after it job can be done by /r. Sometimes even that does not help, and the only thing left is to format the drive. But it's already a discussion between you and me, and I think it's better here to talk about a specific problem which torments those who ask how to solve a problem, right? Thank you.
September 17, 2012 8:44:57 AM

P.S. Why the first step is /f? Because it's finished in a minute, while /r takes hours and hours to process – in 5 stages – all files, clusters and sectors on disk. Finally, /f usually fix the inaccessible drive (e.g. external hard disk).
September 17, 2012 10:28:40 AM

I think it's better here to talk about a specific problem which torments those who ask how to solve a problem, right? Thank you.

We agree again. Perhaps we could also agree on the pointlessness of raising a necro thread which died two months ago.

Best just let it die - again. :D 

September 17, 2012 1:08:16 PM

Right. That thread is dead, but not the reason(s) that make especially external hard drive(s) inaccessible. Our discussion on this issue, and the ways to solve it, is very welcome for anyone who has the same problem.
September 22, 2012 12:09:41 PM

I, for one, find your bickering to be extremely helpful, and I thank you for it. My problem may be the same as the one that so inspired your squabbling, but the context is not quite identical. I would be EXTREMELY grateful to hear your answers to a general question and a specific one (and please feel free to quibble with each other, it absolutely reinforces my understanding of your assertions):

General Question: Forget the question of whether one should start with the /r or /f switch of chkdsk; could you opine as to the difference between using chkdsk and using those free tools recuva and Restoration 2514? Is it likely to be better to first try chkdsk, and only if that fails to try recuva and Restoration? I'm a bit worried that because chkdsk changes the data on the drive (it doesn't just read it), that chkdsk /f or /r could cause irreperable damage to the data by "fixing" things in a way which make data recovery impossible. Should I start with Recuva and/or Restoration, and if that fails do chkdsk? Thanks.

Specific Problem: So I have a WD 1.5 TB drive which just ceased to spin from one day to the next. I got a PCB with identical markings on it from the same type of drive--as a result of which the drive now spins up and is recognized by Disk Management -- as an uninitialized WD 2.0TB drive! I assume that what's going on is that the 1.5TB drive actually contains 2.0TB of low-level storage on it, but the drive keeps 500GB of storage "hidden", partly in sectors marked as "bad" and partly in sectors reserved to receive and hold data from future bad sectors.
If that's true, then would a reasonable recovery strategy for the dead harddrive be:

1. swap the PCB with a good one that specifically has had its list of bad sectors wiped. THen
2. Use chkdsk /f and/or Reuva and/or Restoration to make a stab at file recovery
3. Do a chkdsk /f followed by chkdsk /r (or just a complete low-level format) to rebuild the bad sector info from scratch.

I'm hoping that this procedure might produce an eminently useful hard disk without having to desolder and resolder any chips.

Thanks for any help and clarification you can offer.
September 23, 2012 1:42:08 PM

Hello and welcome to Tom's Hardware Forums.

Speaking personally, I would let it go through the initialising process and give it a quick NTFS format if required. Then, Recuva or Rest2514 will have a fighting chance of retrieving your personal files but I doubt you'd trust it to run an OS again. I've often used PCBs from similar drives and in fact I never scrap a hard drive circuit board - they're invaluable to me. Matter of interest - what does your old PCB do on the 2 Tb disk?

ChkDsk might do some good and is well worth the shot but I can't remember whether it's available before initialisation so you'd have to use the Command Line to kickstart it.

As you've noted and probably have your own view, /f or /r is the question. I agreed with themrvladek that /f is quicker but fixing PCs for a living, I prefer the more thorough /r even though it takes longer. It's still quicker than having to run both if doubts still exist after running /f.

September 23, 2012 5:42:01 PM

Well, that's certainly a point of view I hadn't thought of: make the drive look more tractably hosed as opposed to intractably hosed like it is now, and the let the free software which works on tractably hosed discs do its thing.

I now understand (from a very useful community forum about Western Digital disks) more of what's going on. You ask:

> Matter of interest - what does your old PCB do on the 2 Tb disk?

The "bad hard drive" itself -- consisting of this 2TB disk and the "old" PCB -- doesn't spin up at all. I can't see how to upload pictures into this post, but i could show you that the SMOOTH chip of the old PCB is burnt. THe Marvell MCU doesn't seem damaged at all. Also, the PCB has place for an EPROM at position U12, but there is nothing there. Apprently means that the firmware information about bad sectors is store in the Marvell MCU, so what's really required to "restore" the drive is for someone to unmount the Marvel MCU from the old board and replace the new Marvel MCU with it. That is DEFINITELY beyond my abilities. And given that the vendor sold me a replacement board without telling me that it almost certainly will need to have an MCU transplant, I am suspicious that "for his next trick" he will explain that I need to spend some serious GBPs with him now that "replacing the PCB" didn't work.

Basically, i need to decide amongst the following options;

1. Go back to the unscrupulous board vendor and ask him if he can use the "old Marvel" chip from my old drive to replace the Marvel chip on the new broard. (say for GBP 10)

2. Find a new vendor who will be willing just to move the old Marvel chip to the new PCB.

3. Forget about updating the firmware on the drive and just initialize the drive -- knoing full well that the next step is to run recovery software on the drive.

Choices #1 and #2 are a bit of a pain, but they are very likely to succeed in giving me the oringial deve Choice #3 is easy peasy, but I worry that initializing/formatting/chkdsk will only make the original layout of the drive less, not more, accessible.

Let me know if (and how) you'd like to see the pictures of the PCB.

I'll probably check out choices #1 and #2 tomorrow and go that route before I write the drive in any way.

One last question. if I may: some years ago i paid money for a copy of SpinRite. One of its functions seems to be to test every sector of the drive and write out a new list of bad sectors to the firmware. Does this mean that Spinrite can effectively "recreate" the correct firmware table by brute force, without doing any resoldering? Does the "adaptation" information contain more than a list of bad sectors?


September 23, 2012 7:04:54 PM

I share your fear in going down the "completely hosing" road but if I hadn't had some success with it, I wouldn't suggest doing it. That said, I don't remember if I've done it to an unitialised disk - only unmountable ones.

Another method before going that extreme is to connect the disk to a Linux OS which can frequently mount drives with which Windows finds difficulty. A LiveCD version would so and I use PCLinuxOS from

September 26, 2012 11:05:47 AM

Thank you for the pointer to the LiveCD version of PCLinuxOS. That was news to me. Do you have some favorite Linux (or PCLinux) disk/file recovery software.

Is there a chkdsk for PCLinux, or anything else I could run that might recreate the bad-blocks list or recover files for me?

Oddly(or perhaps not, I don't know), I own a copy of SpinRite, which claims to be able to recover files in this way -- but although Windows recognizes the disk (and just needs to initialize it), SpinRite does not see the disk at all.

I'd prefer to start with software that only tries to read and get the files first, before using something that will potenitally move things around as a result of decisions about bad blocks, for the obvious reason. But right now I seem to have a choice between chkdsk and paying for cross-Atlantic shipping of the drive + $60 for yet another PCB (this time with adaptation).

I sure wish I could find software that would read the firmware from the MCU on the PCB and then write it out again. I understand why such a service is worth $60 (plus $$ for shippng). I'd much rather pay to have the firmware-copying software in my toolbox. (I'd rather learn to fish than buy the fish in this case).

September 26, 2012 6:41:11 PM

My hope for you in Linux would be that it would recognise the disk and make it work properly but if data are in need of recovery, this utility should help:-

If your disk has a PCB problem, bad blocks and even data recovery itself may not be on the menu. I think were I to be in your position, and knowing I couldn't trust that drive again with my OS, I'd buy an identical one and use the circuit board from that disk to rescue the old.