I have a 6 TB external NTFS drive which suddenly appears unformatted.

I imagine that the Master File Table got messed up. Is there any gratis tool which will repair it in-place? Windows or Linux

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    Are you talking about FAT or NTFS? There is no such thing as a FAT in a NTFS filesystem. NTFS has the MFT which has a different structure. Also, can you define "in place"? There is no tool besides chkdsk that will " repair" NTFS, of course only if the damages are minimal. Not to mention the fact that trying to fix a file system rather than extracting the data is a terrible idea if you care about the files. – Andrea Lazzarotto Sep 26 '16 at 9:56
  • I meant an NTFS file system, with whichever tables tell the o/s where to find each directory & file; I believe that is corrupt. By "in place" I mean that I don't have an external drive to recover files to - I believe that the files are still there, and just need to be pointed to again. Can I run chekdsk on a device? There is no drive letter any more. As to your last sentence - I agree, but can't afford a 2nd 6tB drive :-( – Mawg says reinstate Monica Sep 26 '16 at 10:25
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    If this is the case, you should start by recovering the most important parts e.g. on a 1 TB drive. Having said so, are you really sure that the MFT is broken and it's not just a partition table problem? What is the output of sudo fdisk -l when the drive is connected? – Andrea Lazzarotto Sep 26 '16 at 12:00
  • Alas, it is all the most important parts. Yes, it may just be a partition table problem. I am running Windows (hence NTFS), but can install a Linux VM and fdisk from there – Mawg says reinstate Monica Sep 26 '16 at 14:04
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    PS: if 6 TB of data are considered "the most important parts" I would humbly but firmly suggest to always have backups. – Andrea Lazzarotto Sep 26 '16 at 18:02

System Rescue CD is a live ISO that you can burn onto a CD or a USB drive and then attempt repair of your drive.

It is free, gratis & consists of Open Source tools. The kernel supports all important file systems (ext2/ext3/ext4, reiserfs, btrfs, xfs, jfs, vfat, ntfs), as well as network filesystems (samba and nfs)

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  • The Linux tools (in this case ntfsfix) won't help if the MFT is actually damaged. – Andrea Lazzarotto Sep 26 '16 at 11:59

When I had a similar issue last time, someone recommended TestDisk which helped. I wanted to close as a duplicate, but probably it was on a different site, so I give it as an answer.


  • runs on Windows
  • is free and open source
  • can fix partition table, recover deleted partition
  • can recover NTFS boot sector from its backup
  • can fix MFT using MFT mirror

The usability is not ideal for Windows users, but if you have some knowledge about file systems and data recovery, you'll get it working. The Step by step guide is helpful. In my case I was able to fix the HDD directly from the running Windows where the disk got broken - no need to boot a Linux Live CD or something.

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  • A small note on Testdisk: it's bery good when the partition table is broken (and probably it will be OK for the OP's situation). But if the MFT is really broken it won't recover any file. It does not "repair" a broken NTFS in place. – Andrea Lazzarotto Sep 28 '16 at 12:58

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