I'm new to Ubuntu, and I'm trying to install it alongside Windows 10, but the installer shows other partitions not the C: drive.

C is 100GB containing windows 10 and there are 60Gbytes left but I can't choose it. I believe it's /dev/sda2.

What should I choose to keep Windows and all the data and install Ubuntu on the C drive?

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  • 1
    Ubuntu does not use letters to identify partitions. c: has no meaning. You need to resize your windows partition.
    – Panther
    Sep 14, 2017 at 20:24
  • Once you understand your partitions, you install Ubuntu into the free space. See askubuntu.com/questions/203850/…
    – Panther
    Sep 14, 2017 at 20:43
  • i know, But i have no free space. my 1TB HDD is partitioned into 3 partitions C, D and E ( sda2, sda3 and sda4 respectively ), I knew that from their sizes. So should i free some of a partition using disk manager or what ? Sep 14, 2017 at 20:51
  • 1
    Someone has misled you about partioning. See my answer to your other question. You can't install Ubuntu in the same partition as Windows
    – Zanna
    Sep 15, 2017 at 13:08
  • 1
    @Hi-Angel You forgot to mention that selecting an existing partition to format it as ext4 will erase all the data and files in that partition. :O
    – user68186
    Sep 15, 2017 at 14:43

2 Answers 2


When you install Ubuntu alongside Windows it will create new partitions

Based on the pictures and your comments you want to put Ubuntu and Windows in the same partition called 1/dev/sda2 in Ubuntu and C:\ in Windows. This is not possible. Ubuntu will always be in a separate partition. It may also create a small partition called swap for its own purposes.

When you choose Install Ubuntu alongside Windows Ubuntu installation will automatically find the partition with most space and propose to shrink it to make space for the new partitions needed for Ubuntu. This is what your first picture is showing. You can move the divider left or right to allocate more or less space to Ubuntu.

Since you are new to Ubuntu, I suggest you use this option.

I am not sure why the Ubuntu installation does not give you the option to resize the Windows partition. It is possible that the Windows partition (C:\ drive) is fragmented and the Ubuntu installation program cannot shrink it without destroying the Windows files and programs.

If you really want to split the C:\ drive into Windows and Ubuntu partitions, then you will need to boot Windows and use Windows partition management tools to shrink the C:\ drive. Keep the freed up space unallocated/free after you shrink the C:\ drive. Do not create a new partition while in Windows. Ubuntu uses a different type of partition called ext4, and won't use the partition you create in Windows.

When you try installing Ubuntu again alongside Windows, the installation program will find the free space you had created and use that space to create the partitions it needs to install Ubuntu.

Hope this helps


1.If you only have sapce left in C: Drive and you want to dual boot windows with linux you need to "shrink" the space of your C: Drive for that boot into your windows pc and use Disk Management Tool to shrink the space of your C: Drive.

2.In some cases Windows does not allow to create further partions from C: Drive in that case you can use third party software Mini Tool Partion Wizard

3.You can also fallow steps from this answer which is for dual booting windows and linux may help you with Ubuntu also.


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