why am i unable to dual boot windows 10 with ubuntu 18.04?

Question

I have been struggling to dual boot Windows 10 with Ubuntu 18.04. I have Windows 10 already installed with all the latest updates as of 21st July 2018. The problem that I am facing is that when I boot Ubuntu from the USB drive, I am asked to install Ubuntu. When I choose that option, while proceeding I see that there is no option to install Ubuntu alongside Windows.

Only option to erase the disk and other options are available. I looked up in the Internet and found similar problem for Dell XPS model but in that question dual booting was being done with Ubuntu 16.04. In that post it was advised to enable ahci in sata controller option in BIOS mode and to disable fast boot mode. I have done all those things but still option to install Ubuntu alongside Windows is not showing.

What I am trying to say that above option is not showing but all the rest options from second onwards is showing. The laptop that I am using is Lenovo g5080. I have Windows 10 (64bit) already installed and I don't want my data to be erased. Why am I unable to dual boot Windows 10 with Ubuntu 18.04?

disk management system

I am also adding screenshots from Ubuntu installation pages. I don't see "install Ubuntu along with Windows" option as shown below :

and partitions in Ubuntu. the free space is what I intend to use for Ubuntu installation

Answer 1

I had a similar issue trying to install Ubuntu 18.04 alongside Windows 10: the Ubuntu installation page did miss the "Install Ubuntu alongside Windows 10" option.

In my case, the cause of the missing option was:

• my Windows 10 is set up in BIOS / CSM mode (WIN+R -> msinfo32 -> open System Information -> right pane: BIOS Mode shows Legacy), presumably because I had upgraded from Win7
• in my Mainboard BIOS / Firmware setup, UEFI is not disabled (only "UEFI" or "UEFI+Legacy" options are available, I have set this to "UEFI+Legacy")
• to install Ubuntu, I had booted an out-of-the-box Ubuntu 18.04 USB stick which (by default) has both GPT/UEFI + MBR/BIOS/LEGACY capabilities, but...
• here comes the issue: ... since the Mainboard boot device priority was set to boot UEFI USB drives before booting into BIOS USB drives ...
• ...as a consequence, the Ubuntu USB stick would always boot into GPT / UEFI mode (you can tell by checking e.g. if the /sys/firmware/efi directory exists, see the various hints on the net)
• and thus the Ubuntu installation does not find a Windows 10 boot record (apparently looks only for UEFI... what do the experts say?)

I did fix the issue simply by:

• changing the Mainboard boot device priority to boot NON-UEFI devices first (or: you can enter the manual boot menu -> and pick the NON-UEFI USB stick to boot from)
• and then boot the Ubuntu USB stick successfully into BIOS / MBR mode (no /sys/firmware/efi directory)
• et voila: the "Install Ubuntu alongside Windows 10" option appears, and installing Ubuntu parallel to Win10 automatically yielded the desired boot menu with Ubuntu and Windows10 to choose.

Converting Windows 10 to UEFI mode was therefore not neccessary for me.

Maybe this helps also in your case...

Answer 2

Just to be sure, you may want to make a backup of the important data. Normally, nothing should happen to the data you have on Windows, but it never hurts to be prepared in case anything malfunctions.

Start the installation process from the bootable USB. Choose the options that suit you best. When prompted to choose instalation type, select "Something Else" to create the partitions for the OS. To create a partition, just click the "+" sign after selecting "free space" and fill in the information (detailed below). Be careful not to select the Windows partitions. You will need to create the following partitions from the unallocated space on the HDD:

• root
  • Size: 30-50GB
  • Type: Primary
  • Use As: ext4 Journaling file system
  • Mount Point: /
• swap (optional)
  • Size: see this post to decide on a size (and whether you want swap at all)
  • Type: Logical
  • Use As: swap area
• home (optional, see this post for more info)
  • Size: the rest of your free space, generally
  • Type: Logical
  • Use As: ext4 Journaling file system
  • Mount Point: /home

Leave the "Device for boot loader installation" setting to the default value (it should be /dev/sda with no number) and click "Install now". Let me know if you run into any more trouble after installation.

Normally, after installing and rebooting, you should see the GRUB screen prompting you to choose between booting Windows 10 or the newly installed Ubuntu 18.04 (there may be other options too, for going into the BIOS, advanced settings for Ubuntu, but these two are what should matter to you right now). Sometimes the PC boots directly into Windows or Linux, but that's usually a fairly easily fixable error in case you run into it.

Answer 3

I finally figured out all the problems related to my system and was able to dual boot ubuntu alongside windows 10 without any data loss. In these kind of problems the issue is different for different persons depending upon the hardware and type of firmware they have. I will write down the problems and solutions that i specifically faced for future reference. So, if anyone encounters similar problems they can check the following:

1. Check what is the type of your disk in the disk management system in windows. There are two types of them: basic and dynamic. To dual boot as it turns out it should be basic. In my case i had dynamic types originally. To convert it to basic type without any data loss i used aomei dynamic disk converter software. That seems to be the only possible solution in my knowledge.
2. Although the dual booting can be done in old legacy boot mode but in my case i tried many ways to do that but was unsuccesful all the time. So the better option is to change the boot mode to uefi. That makes it a lot easier and error free. To change the boot mode to uefi first check the partition type of your disk. In my case it was classical MBR as pointed out by @mook765. So to convert the boot mode to uefi first you need to convert the partition system to newer GPT partition system. To do that without data loss i used aomei partition assistant. There is another way also as specified by microsoft in this link https://docs.microsoft.com/en-us/windows-server/storage/disk-management/change-an-mbr-disk-into-a-gpt-disk

After you have converted the partition system to gpt you can easily convert the boot mode to uefi. To do that just enter the bios setup of your system and in the boot section change your boot mode from "legacy support" to "uefi" and exit after saving the changes. Now for dual booting the process is very straight forward.the steps are mentioned below:

a. First insert the usb drive having ubuntu iso and then restart your computer pressing and holding shift key until the uefi menu starts up.

b. Uefi menu differs from system to system but there should be an option titled "use a device". There you can locate your usb drive and enter that and installation process can be started.

c. If the "install ubuntu alongside windows boot manager" option shows up you can do that or if you want custom configurations the answer given by @SakoDaemon explains that process pretty well.