Archive for January, 2009

Sysadmin: Recovering deleted Windows partitions

TechnologyI made a mistake the other day: I wanted to delete the partition on an external drive and in my haste ended up deleting the partition of a local hard drive instead…

The good thing is when you delete a partition using the Windows Disk Management console it doesn’t actually delete your files, only the partition header.

Windows Disk Management Console

With NTFS files systems, there is a backup at the end of the partition. The problem is how do you recover it?

I first looked at the instructions from Microsoft knowledge base article kb245725, downloaded the low-level sector editor Dskprobe but was getting no-where with it.

Searching google brings you to the usual list of recovery software that you can’t be sure will actually do the job until you fork $$ for them.
I’ve got nothing against paying for software but I’ve been bitten by false promises before.

My search ended up with TestDisk an OpenSource utility to manipulate and recover partitions that works on almost all platforms.
The user interface is DOS only, so it’s not pretty, not point-and-click user friendly but it has a fair amount of options and after fiddling around with it for 10 minutes, I was able to simply recover the backup boot sector and tada! all my files were back!

TestDisk in action

So, some recommendations when recovering lost partitions:

  • Don’t panic! If you only deleted the partition (whichever type), chances are you’re likely to recover it or at least salvage the files.
  • Obviously, be careful not to write anything over them, like recreating partitions and a file system.
  • If you use a utility like TestDisk, don’t blindly follow the on-screen instructions. At first, it was telling me that I had 2 Linux partitions on the device (which used to be true) but it did not see the NTFS one. Then it thought I had a FAT partition only until I switched to the advanced options and inspected the boot partition.
    Just know enough about file systems to know what you’re looking for.
  • Low-level tools are not for everyone, so if you’re not comfortable using them, don’t tempt your luck and try a paid-for recovery tool with an easier interface.

If you use TestDisk and you manage to recover your files, don’t forget to donate to encourage Christophe GRENIER, the author.


3 comments January 8th, 2009

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