How to recover lost partition using Linux

The partition table describes the division of your disks into partitions. Each partition is formatted into filesystems such as ext4, exFAT, and NTFS before it can be used. When a partition is deleted, only the entry in the partition table is removed while the real filesystem remains intact.

Deleted or lost partition recovery is possible by scanning the disk for existing filesystems and then recreating the partition table based on the found filesystems.

Partition recovery relies on the filesystem remains to uncover the missing partitions. One such application in Linux is testdisk.

Partition recovery tools could only operate on unmounted filesystems. The best way to do it is by using live Linux distribution or installer disk such as the Ubuntu installer.

1. Boot into live Linux distribution or by using Linux installer disk such as Ubuntu.
2. Get into Live CD mode if available if booting from installer disk.

   For Ubuntu installer, click on the Try Ubuntu button.

3. Launch Terminal.

   If no Live CD mode available, press <ctrl> + <alt> + <f2> keys to get to the terminal.

4. List available disks in the systems and identify the disk with the deleted or lost partition.

   $ lsblk
   NAME  MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
   loop0   7:0    0  1.9G  1 loop /rofs
   loop1   7:1    0 89.3M  1 loop /snap/core/6673
   loop2   7:2    0 53.7M  1 loop /snap/core18/941
   loop3   7:3    0  151M  1 loop /snap/gnome-3-28-1804/31
   loop4   7:4    0    4M  1 loop /snap/gnome-calculator/406
   loop5   7:5    0 14.8M  1 loop /snap/gnome-characters/254
   loop6   7:6    0 1008K  1 loop /snap/gnome-logs/61
   loop7   7:7    0  3.7M  1 loop /snap/gnome-system-monitor/77
   loop8   7:8    0 35.3M  1 loop /snap/gtk-common-themes/1198
   sda     8:0    0   20G  0 disk
   sr0    11:0    1    2G  0 rom  /cdrom
5. Enable additional repository if required.

   $ sudo add-apt-repository universe
   'universe' distribution component enabled for all sources.
   ##### snipped

6. Install testdisk using package installer if not readily available.

   $ sudo apt install --assume-yes testdisk
   Reading package lists... Done
   Building dependency tree
   Reading state information... Done
   The following NEW packages will be installed:
     testdisk
   0 upgraded, 1 newly installed, 0 to remove and 316 not upgraded.
   Need to get 345 kB of archives.
   ##### snipped

7. Launch testdisk.

   $ sudo testdisk

8. Use arrow key to select No Log and press [ENTER] to proceed.
9. Select the disk with the lost or deleted partition and press [ENTER] to proceed.
10. Select partition table type of the disk and press [ENTER].

    Intel is the most common partition type with EFI GPT starting to gain popularity.

11. Press [ENTER] to start analysing the disk.
12. Press [ENTER] again to search for possible partitions on the selected disk.
13. Select found partition and press [ENTER] to continue.
14. Select Write and press [ENTER] to update the partition table.
15. Press Y to confirm updating partition table.
16. Press [ENTER] on Ok to proceed.
17. Select Quit and press [ENTER] to return to disk selection menu.
18. Select Quit and press [ENTER] to quit the program.
19. Recheck partitions to confirm that the lost partition table is recovered.
20. Reboot your machine.

    $ sudo reboot