TestDisk is a free software data recovery utility licensed under the terms of the GNU General Public License (GPL). It was primarily designed to help recover lost data storage partitions and/or make non-booting disks bootable again when these symptoms are caused by faulty software, certain types of viruses or human error (such as accidentally erasing a partition table).
Forensics usage of TestDisk and PhotoRec is described on the website.
TestDisk queries the BIOS or the operating system in order to find the hard disks and their characteristics (LBA size and Cylinder-head-sector geometry). TestDisk does a quick check of your disk's structure and compares it with your Partition Table for entry errors. If the Partition Table has entry errors, TestDisk can repair them.
However, it's up to the user to look over the list of possible partitions found by TestDisk and to select the one(s) which were being used just before the drive failed to boot or the partition(s) were lost. In some cases, especially after initiating a detailed search for lost partitions, TestDisk may show partition data which is simply from the remnants of a partition that had been deleted and overwritten long ago.
TestDisk has features for both novices and experts. For those who know little or nothing about data recovery techniques, TestDisk can be used to collect detailed information about a non-booting drive which can then be sent to a tech for further analysis. Those more familiar with such procedures should find TestDisk a handy tool in performing onsite recovery.
Supported operating systems
- Microsoft Windows (NT4, 2000, XP, 2003, Vista);
- FreeBSD, NetBSD, OpenBSD;
- SunOS and
- Mac OS X
TestDisk can find lost partitions of the following file systems:
- Be File System (BeOS)
- BSD disklabel (FreeBSD/OpenBSD/NetBSD
- Cramfs, Compressed File System
- DOS/Windows FAT 12, 16, and 32
- (Classic) HFS, HFS+ and HFSX, Hierarchical File System
- IBM Journaled File System 2 (JFS2), IBM's Journaled File System
- Linux ext2 and ext3
- Linux RAID
- RAID 1: mirroring
- RAID 4: striped array with parity device
- RAID 5: striped array with distributed parity information
- RAID 6: striped array with distributed dual redundancy information
- Linux Swap (versions 1 and 2)
- Linux Logical Volume Manager (LVM and LVM2)
- Mac partition map
- Novell Storage Services (NSS)
- NTFS (Windows NT/2000/XP/2003/Vista/2008)
- ReiserFS 3.5, 3.6 and 4
- Sun Solaris i386 disklabel
- Unix File System: UFS and UFS2 (Sun/BSD/...)
- XFS, SGI's Journaled File System