A drive with all my data is showing as unformatted – what do I do?

Occasionally, when moving a drive to another machine, it'll show up as unformatted. I'll look at some possible causes and actions to take.


I recently replaced my system hard drive and have taken my old internal hard drive out and installed it into a external enclosure. When I plug it in, it shows up on my computer, but without a file system label, only a letter designation (G). Disk management says it is unformatted. It was NTFS as an internal drive. I’m concerned that if I format it, I will lose all of my data now stored on the drive. What steps do I take to format this external drive without losing my files? Or am I missing a step in accessing the information on the drive?

First, don’t format the drive.

Formatting will erase whatever’s on there or, at a minimum, make it more difficult to recover your data.

I do have some suggestions of next steps to take instead.


When the system indicates that a drive is unformatted, it’s the result of attempting to read the master boot record, partition table, or other partition overhead information on the drive and getting something other than the expected data back.

In most cases, this is the result of the data on the disk somehow having been overwritten or otherwise damaged.

Less commonly, it can also be the result of a hardware failure, either in the disk itself or the circuitry connecting that disk to your computer.

Hardware problems are easiest to rule out.

Windows Disk Manager showing an unformatted drive

Try another machine

If you have another computer available, plug the external drive into that and see if it is properly recognized.

If it is, then:

  • You have access to your data (back it up!).
  • You know that there’s an issue with your computer that needs to be addressed.

Verify that external enclosure

Because you indicated that you placed your formerly internal drive into an external enclosure, I’m actually very suspicious that there’s a problem with the assembly.

A working USB interface improperly connected to a hard drive could appear as an unformatted drive.

I’d make absolutely certain that the drive was properly connected to the interface card that’s in that external enclosure. Double (even triple) check that all of the assembly instructions were followed and that the drive is attached the right way.

If you have another known-working hard disk, I’d be really tempted to place that in the enclosure and try it. If it works, then you know that you have a problem with the actual hard disk (which we’ll look into next). If it fails, then you know that there’s either a problem with the enclosure itself, its circuitry, or the connection to your PC.

Data Recovery

If everything seems to be connected and working properly, yet your drive still shows as “unformatted”, it’s time to haul out data recovery software.

Piriform (the company that makes CCleaner) also puts out a free tool called Recuva. Among the other features that they list, they state, “Even if you’ve formatted a drive so that it looks blank, Recuva can still find your files on it.”

Naturally, no one can guarantee complete recovery, but it’s a place to start.

Another tool to consider is GetDataBack. It’s not free, but the free demo version should allow you to determine if the utility will be able to recover anything. If so, the tool might be well worth it. From their feature list: “GetDataBack will recover your data if the hard drive’s partition table, boot record, FAT/MFT or root directory are lost or damaged …”

This would have been moot if…

I’d be remiss in my job if I didn’t point out that none of this would matter or at least it wouldn’t matter nearly as much, if you’d had a backup of the contents of that drive.

Remember the rule of thumb: if it’s only in one place it’s not backed up.

Hard drives do fail and often without warning. That can result in complete data loss.

Whether or not you recover your data this time, resolve to put a backup strategy into place so that the next time that there’s an issue (and please trust me, there will be a next time) the solution is simple to get the most recent backup.


  1. Mike

    I think another cause might be taking one drive out of a RAID array and expecting it to work on its own. Especially RAID 0 drives will be useless without the other drives in the array (which is why it’s probably a risky thing because if one drive fails, the data is gone even though it’s spread across disks).

  2. Tim

    My first step, assuming it is possible, would be to connect the apparently blank drive as a secondary internal drive to a pc and see what that reveals. Probably all the files will be visible, in which case, as Leo so frequently and rightly says: BACK IT UP!

  3. Ken B

    I, too, have seen similar situations involving RAID. However, in my case, the RAID was for mirroring (RAID 1?), so a drive pulled out should be just fine. However, the RAID hardware would reserve the first few sectors of the drive for its own use, and the MBR would follow these reserved sectors. While the RAID knew about this, other systems would not, and would see the drive as being unformatted.

    If the old system (or one with a compatible RAID) is still available, the ones I have used all had a way to turn off these reserved sectors, so that the drive could be taken to a non-RAID system w/o losing any data.

  4. Moshe

    If the drive shows as “Unallocated” like your screenshot, Recuva won’t be able to do anything – it needs a drive letter to work (as far as I can see).

    Well, the image was manufactured so it certainly doesn’t apply in all situations, but similarly there are many scenarios that are or are similar to the question asked where things will still look like that, and Recuva, or GetMyDataBack will often apply.

  5. Glenn P.

    I have also known spurious “unformatted” or “missing disk” errors to show up in connected external USB drives.

    Even before  doing any  of the things that Leo suggests, I urge you to perform a “CHKDSK /X /F” on that drive, immediately, and see if that doesn’t clear up the problem right away (possibly accompanied by a lot  of gobbledygook about corrupted file attributes, or missing pointers, or what-have-you).

    For example, assuming that the drive in question is “J:”, you would click Start, then click on Run…, and then type cmd in the “Run” dialog box that opens, and click OK.

    In the resulting Command Line box, you would type:

                                   CHKDSK /X /F J:

    Hope this helps. Good luck!!!

    • Karim

      Hi Glenn P
      I had an external HDD connected to my Windows 8 PC that had ALL my files on it, photos, work records…etc
      I reinstalled Windows on my PC as i had bought a new SSD and after that my external HDD was unusable, showing as unformatted, unallocated, and i couldn´t access my files.
      I used Recuva but unfortunately it said it can´t recover HDD that is unformatted, and i did not want to format it.
      I used Easeus which recovered about 225GB ( although i had 348GB ) on my HDD, but at the end of the process it asked for a 70$ payment to recover the files, so i kept searching until i found your post, i followed your instructions and BINGO! it worked.
      I must say you are a genius and i can´t thank you enough!
      Thank you very very much

    • Mike M

      Glenn P. You saved my day! when I booted up XP this morning, one of my 500GB internal SATA drives (Western Digital) showed unformatted in Windows Explorer.

      Your suggestion to use CHKDSK /X /F J: fixed it! The final message CHKDSK wrote to the console was something like “Correcting errors in the volume bitmap”. Also, I noticed that shortly after CHKDSK started the drive’s volume name “Hurricane” (don’t laugh) reappeared. (In Windows Explorer the drive was showing as “Local Disk” before I invoked CHKDSK).

      So a big thank-you from me. But what might have happened when the PC shut down last night to cause this?


  6. Gary H

    When I have cloned my C drive to another drive and placeed it in an external enclosure to use as a backup disk, the same thing happens. However, if I put it back as the original C drive, all of my data, programs and boot works.
    Try putting it back as your original C Drive and see if it will boot and everything is there. Then back it up before you replace it this time.

  7. steve

    Glenn P. mentioned using chkdsk on a troublesome drive from the run dialog box. Now I am not familiar with the various checkdisc commands from the run window, but I have been told that running checkdisc from windows with the fix system errors and recover bad sectors can make a screwed up drive worse and is not a good idea. Any advice???

    Actually it’s all an argument for backing up so that you don’t need to go this route Smile. Sometimes, depending on the type of problem, CHKDSK has been known to make things worse. It’s not common, and in general CHKDSK is quite safe to run. Most often the types of “make things worse” things that happen are disappearing files, which then call for a utility like Recuva to recover.

  8. David

    I would agree, agree, agree with the back-up comments. Can’t have too many drives for that purpose. I have no less than six (overkill possibly, I would concur!), on my main computer and two on an older machine, all backing up documents and about 105 gigs-worth of music and nostalgic audio clips that I have done a great deal of work on in the way of editing, cleaning up, etc; over many years and are now irreplaceable. Accidents can still happen and after I tried out a certain new defrag/optimise program (which had better remain nameless) on one of my drives, I “lost” several thousand music tracks, which I deduced were actually still there, judging by the used space, which hadn’t changed. On that occasion, CHKDSK made them visible again, so I assume the program had partly hosed the file system. Felt OK, though, knowing I had a fall-back plan.
    Leo is absolutely right. Back-up as though your life depended on it!

  9. Daniel

    I’m a real novice at this, so I could be waaaaaay wrong. But could it be as simple as needing to change the jumper settings on the hard drive from “master” to a ‘slave’ drive?

    When used in an external drive enclosure, that would not apply. (Not would it if the drive were a SATA drive.) That jumper only applies to IDE/PATA drives installed internally. In which case you’re absolutely right. Smile

  10. Dennis

    The symptoms you describe indicate that your partition table on the drive may have been corrupted. Unrecognizable partition table = no file structure = unformatted drive, as far as the OS is concerned. That can be caused by a virus or a software program that does not behave like it’s supposed to. To recover, try a free utility called “Testdisk”; it’s the best I’ve found for testing and fixing the the partition table and/or MBR of a hard disk. You can find it at: http://www.cgsecurity.org. It’s a DOS screen (command-line with DOS menu structure) utility that runs under DOS, and all versions of 32 bit and 64 bit Windows. Suggest that you download and look at the on-line documentation on the site before using. Do the deep search – the recovery process will take longer, but is more thorough, in my experience. It comes with a companion utility (they’re both installed at the same time) called Photorec, which provides powerful data and file-recovery capabilities. Neither Testdisk nor Photorec will ever win any user interface awards, but in my experience, they plain flat do the job! I’ve been able to successfully recover the partition table and all of the files of a “raw” (unformatted) hard disk several times as needed when nothing else that I tried even came close. Hope this helps!

  11. David

    It also happened to Me. I had to reformat and and re-install winXP.My secondary drive with all My files had the letter E/ assigned to it the first time and after the install it can out as letter D/ when I tried to open it all the folders appeared as empty;but I restarted My computer again and windows started to correct the problem by itself. It had something to do with orphaned files.This has happened twice(reinstalled twice)so now I just let it BE,it will come around to fixing itself.

  12. Ezra Ben-Meir

    Re “lost” data on external drive:
    I had the same problem when getting a new computer & OS.

    Solved the problem by changing the jumpers- to pins NOT suggested on the drive labels itself.
    Just keep changing the pins in all sorts of different arrangements

  13. narumanchianji

    you have given very useful tips. but you forgot the first tip!. remove the drive from external enclosure and put it back in your system as internal drive. if it shows all files the problem is with external enclosure. if it does not show even now, then the drive has become bad and needs the other tips you have suggested.

  14. Vivek Wilfred

    You may also want to try TestDisk (Windows 32-bit): http://www.cgsecurity.org/wiki/TestDisk_Download

    After downloading, extract it, browse to the ‘win’ folder and double-click testdisk_win. In the first screen choose you may choose anything, in the second screen choose the relevant drive (the drive in the enclosure), next choose ‘Intel’, next choose ‘Analyze’ and then ‘Quick Search’. You may get options to change partition type and recover depending on the results.

    Another way you try would be to choose ‘Advanced instead of ‘Analyze’ above and try to recover ‘Boot’ or do an ‘Undelete’.

  15. Mark Jacobs

    You can get a second external drive with at least 1.5 TB (more is preferable). You can also subscribe to an online backup service such as Backblaze or Carbonite choosing the option which allows for backing up external drives. I do both.

  16. Bob Greene


    With a USB enclosure-based drive, the “Drive not formatted” (DNF) error often turns out to be completely false. That is, the physical drive and the data, itself, is still perfectly OK, but for some reason (related to a faulty physical (data cable) connection, or perhaps a glitch in the external USB enclosure circuitry, or maybe a corrupted data structure on the drive), the drive is no longer recognized by the main system.

    Unfortunately, USB enclosures are notorious for the DNF problem, often noticed during insertion or removal of the USB data cable. In some (extreme) cases, if the data cable is accidentally bumped, problems appear immediately because the enclosure’s USB connector is wobbly.

    SOLUTION– remove the drive from the enclosure and reinstall in the main (host) system. On booting the system, does the drive (volume) display now? If not, it is time to run a Windows utility called “chkdsk”.

    Reboot the system, pressing the F8 key every second or two when the opening messages (white type on black screen) start scrolling by. Soon, you will see the Windows Advanced Options screen. Highlight item #3 “Safe Mode with Network Connection” and press enter.

    When the single command line prompt appears, type in this text– “chkdsk /R” (a space between “chkdsk” and “/R”) and press enter. Now, the system will analyze the problem for you automatically, and make repairs. This process takes a considerable amount of time, so have lunch while the process chugs through your drive’s logical structure, correcting errors and missing/corrupted elements.

    Depending on drive size, it could take much longer than one hour. Note of Warning– try not to interrupt or stop the chkdsk /R process. Let it run, even if it seems to take longer than it should. For all you know, there may be many errors and this will take time to repair (the purpose of the /R switch). To assure uninterrupted testing, it is wise to support your main system with a UPS, so momentary power drops do not crash the testing.

    When chkdsk is finished, you will see a screen prompt to that effect. Look over the summary immediately above, and see whether any bad sectors are reported– an indicator that these small areas have been set “off limits” to the operating system, and will not be used for data. Now, type in “exit” on the command line to close the command window. Reboot into a normal Windows session.

    After reboot, go to My Computer or Windows Explorer to verify the system now displays the drive with its original volume name / label (most drives have a name of some sort given during the last formatting). If that name reappears, you are OK and back to normal.

    But there may also be other, hardware-related damage, as well, which can be estimated by the number of bad sectors found, and the rate at which these increase over days or weeks of running chkdsk (keep a record). The most important thing now is to backup the data, while you have the chance. If there is hardware damage, chkdsk /R permits you to have at least one more stable session with the drive, in order to off-load your data.

    As Leo comments, DNF error messages could indicate a problem with the USB enclosure’s circuit board, a bad USB cable and/or connection, or both. To find out, reinstall the problem drive in the USB enclosure, power on, and reattach the USB cable to the main system. If the drive is not recognized again, or the DNF or any other error appears, the finger of suspicion is now pointed at the drive enclosure and/or USB cable connection, but not the drive, itself.

    Most likely, the chkdsk /R recovery method will work for you time after time. But in the long term, a recurring “chkdsk /R” fire drill could become a bother. In that case, be sure to check out the enclosure as Leo prescribes– if the enclosure has even a shadow of a doubt about its reliability, try the problem drive with a different USB enclosure, and compare performance (using a new USB data cable with the different USB enclosure).

    NOTE: Hard drives, particularly those running at 7200 rpm or higher, require good ventilation in a USB enclosure. They usually do not get it from a simple, aluminum “heat dissipating” shell, and drive problems can appear quickly after only 30 minutes of operation. Suggestion– Google for “ventilated USB enclosure” to find a good enclosure that can keep a hot drive cool. For example, a recent Google search turned up a USB enclosure that runs either USB2 or USB3, with an 80mm fan– http://masscool.com/product_detail.php?pid=181&id=175

  17. Glenn P.

    This is for both Gary H. and for Leo, who questioned whether CHKDSK /F was safe to run on a drive that had suddenly appeared unformatted:

    Guys, if the worse that CHKDSK does is to “vanish” a file or two, versus  leaving your drive unformatted with hundreds (or, thousands?) of your precious files inaccessible, I’d gladly call that a step forwards, not backwards.

    I mean, think about what you’re saying — your system is already reporting that drive worse  than empty! How much worse than that can it possibly get?!

    At such a point, unless the proposed “remedy” in question is known to be truly dangerous or foolish or otherwise risky to your data, you can’t lose much by trying it. Now, I’ll grant you that at such a stage that there are LOTS  of things that will qualify in that regard — but a simple CHKDSK /F just doesn’t  fall into that category. Fortunately.

    So: By all means — CHKDSK /F first, and then (if need be) Recuva afterwards.

    That was (and still is) my recommendation.          :)

  18. Sue Binns

    Hello there.
    My computer trouble started with Unmountable Boot Volume, and then S.M.A.R.T Status Bad. My computer wont boot now not with UBCD4WIN disk.
    Pressing F1 didnt do anything, the only thing I could do was go into Bios F2. I was able
    to disable S.M.A.R.T and install UBCD4WIN that I had built with XP disk and plugins.
    I have received some error messages from the plugins that I have used. I am flumexed.
    I am using Win XP.

    Run Scanner Error: No windows installation found.

    Handy Recovery: No valid supported file system present on the volume/The volume does
    not contain a recognised file system. Please make sure that all required system drivers
    are loaded.

    Remote Registry: Runscanner error. Target is not windows 2000 or later.

    Drive Image XML 2.13: The disk in drive c is not formatted c: is not
    accessable. The parameter is incorrect.

    X:programautobackup: The specified path does not exist. Check the path and then…..

    DBX Tract: The target is not windows.

    Disk Investigation: Division by zero.

    CHKDSK: Is not available for raw drives.

    Test Disk: Disk in drive c is not formatted. Do you want to format it now.

    HD Tune 2.55: Error: Reallocated sector count failed.

    Drive Image 2.13: Stream write error. Info Appexc. Address 004165Bb. Stack Dump.

    Win Dir Stat: My Computer 2.7GB. 26,777 items. (D:) 2.3GB. 23,240 items.
    Ramdisk (B:) 1.8MB. 67 items.
    UBCD4WIN (X:)3,467 items.

    Windows XP Setup: Setup was unable to open error code 0x2 at line 2088999411

    I am desperate to retrieve a childrens computer book with illistrations
    that I have written, photo’s and my dads family tree from my wonky laptop.

    I ran Driveimage XML PE 2.13 and got the message:

    Drive/Partition Logical Drive Type Capacity
    Disk 0#1 ? NTFS (7) 55.9GB
    Disk 1#1 D:() FAT 32 (11) 3.81GB

    I ran Recuva and got the message: The path does not exist.
    I am trying to retreive data. I was just a about to format C:
    so I could use Recuva as I got “The path does not exist” erorr. But before I did
    I wanted to back up with Drive Image XML and then to Windows Disk Management:

    Vol (C:)
    Layout Partition
    Type Basic
    File System BLANK
    Status Healthy active
    Capacity 55.88GB
    Free Space 55.88GB

    Vol (D:)
    Layout Partition
    Type Basic
    File System Fat32
    Status Healthy
    Capacity 3.08GB
    Free Space 1.48GB

    Vol ubcd4win
    Layout Partition
    Type Basic
    File System CDFS
    Status Healthy
    Capacity 428MB
    Free Space 0MB
    When I try and backup

    Drive Label Type Capacity Used Physical
    C: .C 55.9GB 100% DISK 0#1

    I get this message:
    Cannot create volume information (NT, Cluster size = 0
    info: APPEXC
    Address 004E1COD

    Stack dump

    Now after seeing this am reluctant to format C: and run Recuva, but I dont know how
    to get to the data. Is formatting and recuva the best way.

    Thank you.


  19. Maurice Lampl

    I have Seagate external drive (F) as backup drive. Now I am getting this error message that the drive needs to be scanned and repaired. I’ve clicked on this and this message keeps coming back…

  20. Minna Shally

    Hi! There!
    “Not formatted” problem is not a big deal.
    All one is supposed to do is simply to select a reliable recovery tool for regaining the files inside it and format this drive to make it usable again afterwards.
    As to the reliable recovery tool, one should try a free recovery utility, which has helped me restoring my documents, images, videos, and other files from my mistakenly formatted drive.
    Read much more things of this freeware there:
    1. Never attempt to write new files on this drive to rewrite the original files. The rewriting thing can cause data loss permanently.
    2. Never save the recovered files on the same drive in case of recovery failure.
    3. Never forget to format this drive to return its normal use.
    4. Never forget to back up the important data in the future.

  21. Rvind

    Hi, i have unallocated disk space to tried to extend my C:\ (XP) using minitool software .
    After an hour system restarted and never booted again.
    Tried to boot using boot files but failed.
    Tied using XP disk but asking for Administrator password, which I dont remember.
    Hence as a lost resort, Installed XP again, but on different hard. I can open my original C:/ to get my files from desktop and my documents.
    Drive is not formatted, can I get my files back.
    Please help

    • Reza

      I would suggest you to try Partition Find and Mount — free partition recovery software. Scan(intellectual) will show you some unmounted drive/space. Try to mount as different drive and exit program without unmounting the mounted drive(important). recover the data in external, because I think you will have to format the drive anyway for full functionality!

  22. ali tayebi

    hello..my x box360 memory unit is 5 GB and if i want to play some games like watch dogs or GTA it needs hard recently I decide to buy an USB32GB and if i configure the usb xbox says it is unformated i formet it to FAT32 but it did not change……..what should I do to repair it??help me plz

  23. Reza

    Great blog! Helped me a lot. Partition Find and Mount worked like magic!
    In my case, I had to increase the C drive, but my windows version was somehow a tweaked one so it does not include the windows partition manager. I installed Paragon partition manager and reallocate some space from E to C. But on the way of working something failed and process aborted after 3-4 hours of moving data! But after the windows start, I see my E drive which contain my all the media (very important marriage ceremony pictures and family videos plus many more age old important files) as unformatted and can not access. I was really scared that it could be a disaster. GetDataBack did not work because it can not access. After failed trying with Recuva I tried free version of Partition Find and Mount — free partition recovery software. Which seems was not working, but after trying Scan (intellectual) I found unmounted drives and mounted as separate drive and exit the application without unmounting. It worked as magic, though somehow I don’t have write protection since it’s a mounted drive. But I can recover all my data and then resize and organize my drives.

    • Tiff

      Thank you for your suggestion of Partition Find and Mount! Even though I had Carbonite backing up my external hard-drive I had many video files and others I hadn’t yet designated for back-up yet. Like you, after trying every suggestion found, I used Partition Find and Mount, I was able to mount my drive to a different drive-letter and copy all my files over to another external HD I have. Saving almost 1 TB of data. I started with the free version, but it was a slow transfer, so splurged $44 for the pro and wow. Breathing normal again!

  24. Steve

    I have been researching this issue on and off for a while now. In my experience, what has worked best is the ‘try another machine first’ approach. For the most part solutions assume there is something wrong with the disk logical file structure, but sometimes the situation is that a drive will not mount on a particular computer while it is recognized normally on most others, even those with identical hardware and OS as the problem machine. In this case I suspect it is a registry problem. If anyone has any insight into this aspect I’d be very interested to hear.

  25. Reza

    I have a 1 TB seagate Ext. Hard.I had divided it to 3 partitions.I decided to make one of them bootable (by some app) to install Win 7 on my PC. Unfortunately It crashed and it caused all 3 partitions appear as one unformatted partitions and MFT was corrupted.2 of them was NTFS and one of them was FAT32. Could you please help me?I had 900 GB variety of useful files on it.I’m baffled!

  26. varoun

    I have a 1TB HDD, with 4 partitions, yesterday one of them started showing as unformatted, I have tried CHKDSK /X /F, I get a lot of file record segment ## is unreadable, then one problem in the index, it recovers lost files, but it still does not fix the problem. I am not able to use recurva.

  27. Mike M

    Help! I’ve got exactly the same “drive unformatted” problem again this morning as I did yesterday morning!

    Once again, CHKDSK /X /F J: fixed it. Once again, the same error fix: “Correcting errors in the volume bitmap”. The drive is back.

    So what is causing this brand-new SATA drive (500GB WD) to fail? Has it got bad clusters or something? How can I lock them out? I thought maybe CHKDSK would do this, but it seems it only corrects the logical errors it finds.

  28. Muhammad

    Hi i went through your blogs regarding the IT support, I have Samsung laptop and for last one week it is given me problem, my laptop hard drive has 2 partition by the name of C and D, whatever iam doing on C drive like to open my computer or documents it is taking too long and the main reason to message you is that it is showing a D drive partition in ‘MY COMPUTER’ but it is not opening, and all my data is saved in D drive, I even tried to installed new windows 7 but still is same, I tried to use option of disk defragmenter but it’s say ‘invalid parameters’ I tried to used bitlocker option but same message I got invalid parameters, I don’t want to lose my data, iam confused that if the problem is with hard drive then why C drive partition is working and D is not, when I right click on D drive for properties it Is taking too long, I will highly appreciate you if you can help me I don’t want to lose my data thanks

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