To install ubuntu in my windows laptop, I need to shrink my disk space into two sections, windows C drive and unspecified space. However, given my 350Gb empty space out of 650Gb in C drive, available shrink space contains only ~4700Mb after defragmentation with program "Auslogics DiskDefrag".

Right now I still don't have enough space for my new ubuntu system. Of course I might try to delete more files, or keep my ubuntu system size as small as a few Gb, but I would like to have at least 250Gb for flexibility and file storage. Would anyone has any explanation on why there are so few available shrink space after defragmentation, and what else I could proceed to maximize my shrink space into 250Gb?

Update : I went through the ubuntu installation and accidentally wipe out the whole windows. So I decided to clean up the whole disk and reinstall windows and ubuntu in an easier manner. Thanks everyone though.

  • the Volume Shadow Copy service detects the activity and creates backups. The tool should be updated to be VSS aware Jun 13, 2016 at 4:09
  • There are unmovable files in Windows; if they sit in bad spots (like the end of the partition), you cannot shrink it. Check for hiberfile.sys, pagefile.sys, and such; but those are the typical two. Switch off Hibernation and and all swapping, then reboot, the files should be gone, and that should solve the issue.
    – Aganju
    Jun 13, 2016 at 4:52
  • 1
    Possible duplicate of How to shrink Windows 7 boot partition with unmovable files
    – DavidPostill
    Jun 13, 2016 at 7:52

1 Answer 1


Here is what I did:

  1. Before resizing the partition, backup your data.
  2. Log in to Windows, and run chkdsk /f C: (replace C: with your partition/drive name). This command check and fix any potential errors.
  3. Boot in to a live Ubuntu CD/USB. Install gparted and ntfsresize (the package is ntfs-3g/ntfsprogs, just install both of them) if they are not yet on the live CD.
  4. Run gparted to view your disks and partition. Note the partition that you want to resize, for example, /dev/sda1.
  5. Resize the partition with ntfsresize (from a terminal):

    sudo ntfsresize -m 400G /dev/sda1

Here, 400G is the size of the new, and /dev/sda1 is the device that you want to shrink. More options for ntfsresize here: ntfsresize. This step can take quite some time, depending on the amount of data that ntfsresize has to move. After this step, you will have a 400G partition for Windows, and a blank space.

  1. Create a partition from the blank space with a tool of your choice.

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