Ubuntu Install Unknown Partitions

by Scanevaro   Last Updated November 14, 2017 19:02 PM

So i want to install Ubuntu and im booting from USB. Im new to Ubuntu.

When i click SOMETHING ELSE, it shows 4 partions: the first of 1mb, sda1, unknown free space, second of 100mb sda2 (that i know its system recovery from win7), third is 170gb (win7) sda3, and the last one is like 830gb, i dont know where this came from.... on windows i have them separated.

is this a bug or something? How to install without losing all my data and keeping Win7?

When i try without installing i get to see my 3 partions (170gb, 600gb, 230gb) but not when i try to install.


ubuntu@ubuntu:~$ sudo gdisk -l /dev/sda

outputs this:

GPT fdisk (gdisk) version 0.8.7  
Partition table scan:
  MBR: MBR only
  BSD: not present
  APM: not present
  GPT: not present

Found invalid GPT and valid MBR; converting MBR to GPT format
in memory. 

Disk /dev/sda: 1953525168 sectors, 931.5 GiB
Logical sector size: 512 bytes
Disk identifier (GUID): 2729AEE7-A594-4A07-91DF-96116B581067
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 1953525134
Partitions will be aligned on 8-sector boundaries
Total free space is 2044 sectors (1022.0 KiB)

Number  Start (sector)    End (sector)  Size       Code  Name
   1              63            2047   992.5 KiB   4200  Windows LDM data
   2            2048          206847   100.0 MiB   4200  Windows LDM data
   3          206848       245762047   117.1 GiB   4200  Windows LDM data
   4       245762048      1953523119   814.3 GiB   4200  Windows LDM data


ubuntu@ubuntu:~$ sudo fdisk -l

outputs this:

Disk /dev/sda: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x13344b63

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1              63        2047         992+  42  SFS
Partition 1 does not start on physical sector boundary.
/dev/sda2   *        2048      206847      102400   42  SFS
/dev/sda3          206848   245762047   122777600   42  SFS
/dev/sda4       245762048  1953523119   853880536   42  SFS

Answers 2

Your disk is set up with the Windows Logical Disk Manager (LDM) system (aka "dynamic disks"), which is a proprietary Microsoft layer atop regular partitions. LDM is conceptually similar to the Linux Logical Volume Manager (LVM), but the two are incompatible formats. In any event, you cannot install Ubuntu on the disk in its current state -- at least, not easily. (It might be possible to cobble something together, but even for a Linux guru, that would be a bit of a challenge.)

The easiest solution is to convert from LDM to a more conventional partitioning setup. Some commercial Windows tools, such as EaseUS Partition Master and Partition Wizard, are supposed to be able to do this losslessly. The tools that come with Windows can do the conversion, too, but only by starting with a clean set of partitions (thus effectively wiping your data). Of course, if you're willing to back up your data and know how to restore your system to bootability upon restoring it, this may be an acceptable solution. (For that matter, I strongly recommend backing up all your data before attempting to convert the disk in any way; although the conversion is likely to be simple, the consequences of a bug, power failure at an inopportune moment, or other problem could be catastrophic.) Some people have reported success with wiping the partition table and then using TestDisk to create a new set of partitions, but I recommend against this because there's no guarantee that the filesystems in an LDM setup will be contiguous, which is an assumption of TestDisk. Thus, TestDisk will work if that assumption is met, but if it's not, you could end up with corrupted filesystems and at least some lost data.

Another option is to buy another disk and install Linux on it. That way, you can leave the Windows LDM configuration alone and let Linux control the new disk.

FWIW, Windows has a habit of converting from a conventional configuration to LDM whenever you create a setup with more than four partitions on a disk. AFAIK, Windows doesn't warn you about what it's doing -- or if it does, the message seems to leave little impression, because I have yet to see anybody ever mention it. Thus, you should never use the standard Windows partitioning tools to add partitions, particularly if you know you'll be exceeding four partitions, unless you're willing to use an LDM setup. (A common newbie mistake is to use Windows to create a partition for Linux prior to running the Linux installer. This often pushes the partition count over four and creates more work to undo this problem.)

Rod Smith
Rod Smith
March 22, 2014 18:44 PM

Shrink LDM partitions from inside Windows

Then free space appears and you can install Ubuntu there.

Shown at: https://askubuntu.com/a/521195/52975

Disable Page File and System Protection to shrink disk fully

As shown at: https://superuser.com/questions/1017764/how-to-shrink-a-windows-10-partition/1060508#1060508

Otherwise, Windows has some unmovable files, and you can't shrink the partition as much as you'd like.

Ciro Santilli 刘晓波死 六四事件 法轮功
Ciro Santilli 刘晓波死 六四事件 法轮功
November 14, 2017 18:53 PM

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