The "Install Ubuntu alongside Windows 10" option not available

Question

I am currently running Windows 10. I have 3 more local drive partitions namely D, E and F along with C drive and System Reserved G drive. I want to install Ubuntu 18.04 LTS in C drive (which also has Windows 10) which has around 75GB free space out of 150GB. My computer uses BIOS and not UEFI.

I am not getting Install Ubuntu alongside Windows 10 option, so I saw some videos on Youtube and saw that they are shrinking the space of C drive. But I am only getting 4440 MB available to shrink but I have 75 GB free! I want to have at least 20-25 GB for Ubuntu.

How can I increase the available shrink space of C drive?

Also, can I install Ubuntu in F drive which is of 180GB size? I can move the files from F drive to any other drive for that matter. Will I still get the option to load either Windows 10 or Ubuntu in the boot menu?

score 1 · Accepted Answer · edited Jun 12 '20 at 14:37

Shrinking the C: drive

I want to install Ubuntu in C drive (which also has Windows 10) which has around 75GB free space out of 150GB.

I am only getting 4440 MB available to shrink but I have 75 GB free!

How can I increase the available shrink space of C drive?

Your disk usage seems to be fragmented. You can try two methods to solve it:

Defragment it in Windows, then shrink in Ubuntu installer

Boot Windows and run defragmentation tool (“Disk Defragmenter” or “Defragment and Optimize Drives”) on the partition where you want to reuse the space (C: in your case).

If this does not help, you can give SDelete (download it from Microsoft) a try to fill the unused space with zeros, so it gets actually free to reclaim.

sdelete.exe c: -z

More information: https://www.howtogeek.com/312883/how-to-shrink-a-virtualbox-virtual-machine-and-free-up-disk-space/

Shrink in Windows

You can also use the Disk Management app in Windows to shrink the disk. You might get better results when processing a Windows drive with a Windows tool.

Size of the Ubuntu partition

I want to have at least 20-25 GB for Ubuntu.

25 GB is the required minimum for Ubuntu Desktop. The installer may disable the “Install Ubuntu alongside Windows” option because the available space which it’s able to get is less than recommended.

Reusing the F: drive

Also, can I install Ubuntu in F drive which is of 180GB size. I can move the files from F drive to any other drive for that matter.

If the data can be fit into another partition, I would choose this option and get more space for Ubuntu while keeping some free space on the C: drive. In the installer choose “Something else”, then select the F: drive. Since Ubuntu does not use the Windows drive names like F:, it’s up to you to choose it correctly. (You can check your partitions order in Windows Disk Management before installation.) Make the partition your root partition (mount point /). Format it as ext4 which is default in Ubuntu. You don’t need to create any additional partitions for Ubuntu 18.04.

More information: How to use manual partitioning during installation?

Will I still get the option to load either Windows 10 or Ubuntu in the boot menu?

Yes, you should get the option in either way of dual-boot Ubuntu alongside Windows installation. However, there are cases when something goes wrong (like in Unable to boot into Windows after installing Ubuntu, how to fix? or if you select a wrong partition to overwrite), so you won’t lose anything if you make a backup of the complete drive before Ubuntu installation.

I have done a disk defragmentation on C drive, now it shows only 791MB available to shrink. Also run SDelete but to no avail. How to use the F drive for installation of Ubuntu? — Apurba, Jun 06 '18 at 10:03
@Apurba I’ve updated my answer regarding this. You can also try to resize the C: partition in Windows. — Melebius, Jun 06 '18 at 10:12

score 1 · Answer 2 · answered Sep 02 '18 at 08:52

I faced the same problem. I was not getting boot alongside windows option. After few tries I got to know the reason which caused it. Ubuntu pendrive was booting in uefi whereas my windows was in bios. So even changing to legacy and disabling secure boot was not helping. While booting from bios screen you will have multiple options in the last screen for over riding. In this two will be of the bootable pendrive you inserted. One will be uefi and other without uefi. Select the one without uefi. And start installing. You will get boot alongside windows option. Hope it helps.

score 0 · Answer 3 · answered Jun 06 '18 at 05:59

You don't need to shrink anything, especially since you have spare room. boot the live cd

Boot the live usb/cd
select 'try ubuntu' at the boot up screen
select 'install ubuntu' on the desktop.
installation type: "Something else" scenario.
select the free space, and choose ext4 and select mount point to be "/" and install.

google guides for 'something else' installation type for ubuntu 18.04. if you want to see some pics/details.

You can set up swap and /boot partitions as well, but with 18.04 its not necessary.

Ubuntu 18.04 uses a swap file instead of a swap partition by default on fresh installations. — karel, Jun 06 '18 at 06:54

score 0 · Answer 4 · answered Jun 06 '18 at 06:11

I recommend you to install Ubuntu on your F drive, if you can't shrink your C more than 4 GB. Be sure to select the correct drive when you install Ubuntu !

When you install Ubuntu, you usually also install Grub, which is a boot loader. It'll give you the option to either boot on Ubuntu or "Windows recovery mode" or something. This "Windows recovery mode" will give you the ability to boot on Windows normally.

I think this guide will be useful to you : https://help.ubuntu.com/community/WindowsDualBoot

This thread here may also help you : How to use manual partitioning during installation?