Unable to Install Ubuntu Alongside Windows 10 on ThinkPad P50 (Model 20EQS34100)

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Problem Description: I need help installing Ubuntu 22.04 LTS alongside Windows 10 on my Lenovo ThinkPad Model 20EQS34100 (P50-series). The installation problem

During manual partitioning, the Ubuntu installer shows all my partitions, but:

  • The “Device for boot loader installation” drop-down does NOT allow selecting my internal SSD (sda / KingFast 256 GB).
  • Only the USB flash drive (sdb) appears selectable.
  • Because of this, the “Next” button stays greyed out and installation cannot continue.

My disk layout (MBR, Windows 10)

Internal SSD: KingFast 256 GB
Partition table: MBR (msdos)

Existing partitions:

  • sda1 – NTFS – 52 MB (System Reserved)
  • sda2 – NTFS – 150 GB (Windows OS)
  • sda3 – NTFS – 530 MB (Windows Recovery)
  • Free space – 104 GB (created for Ubuntu)
  • From this free space we created:
    • sda5 – Ext4 – 94 GB – mount /
    • sda6 – swap – 6 GB

Installer recognizes them correctly, but still refuses to allow selecting sda for the bootloader.

System information

  • Laptop: Lenovo ThinkPad P50-series
    • Model number: 20EQS34100
  • BIOS version: N1EET69W (1.42)
  • BIOS date: 2017-06-28
  • Boot mode: Legacy Only (UEFI boot fails to work with this USB stick)
  • USB installer created with: Balena Etcher
  • Ubuntu version: Ubuntu 22.04.4 LTS (desktop ISO)

What we already tried

  • Booting in Legacy Only, UEFI First, Legacy First.
  • Recreating partitions manually.
  • Recreating USB installer using Balena Etcher.
  • Rebooting into installer many times.
  • The installer always prevents selecting sda as bootloader target.

What help we need

  • Why does the installer refuse to allow selecting the internal SSD (sda) for GRUB installation?
  • Is this caused by MBR disk, Lenovo BIOS quirks, USB creation method, boot mode mismatch, or something else?
  • What is the correct way to install Ubuntu on this machine alongside Windows 10?

Any guidance would be greatly appreciated.
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2

swap doesn’t need to be created since Ubuntu creates and uses a swap file by default. Do you have Bitlocker/Disk encryption enabled on Windows? Maybe that’s causing issues.

2 Likes
3

[quote=“leksanich, post:1, topic:72577”]

Thank you for your response.
Windows BitLocker / disk encryption is not enabled on this system.

The problem we face is that the Ubuntu installer (manual partitioning) does not allow selecting the internal SSD (sda) as the bootloader installation device, even though free space and partitions are visible. Only the USB stick (sdb) is selectable. Because of that, the “Next” button stays greyed out.

We are trying to install Ubuntu alongside Windows 10 on:

  • Lenovo ThinkPad P50 (model 20EQS34100)
  • BIOS: Legacy mode (no UEFI boot entries)
  • Disk: MBR
  • Existing Windows partitions:
    • sda1 – NTFS (System Reserved ~52 MB)
    • sda2 – NTFS (Windows 10 ~150 GB)
    • sda3 – NTFS (Recovery 530 MB)
    • ~104 GB free space we want to use for Ubuntu

Ubuntu installer shows the disk, we can create / and swap partitions, but cannot select sda for the bootloader, only sdb (the USB).

Any advice on how to make the installer accept the internal drive for GRUB would be greatly appreciated.

4

Hello,

I’m not shure, but i once had a similar problem: the parted-tool wasn’t able to write on ntfs-partitions, therefore i had to install a ntfs-3g addon…?

But if you already resized the ntfs-partition this might not be the reason?

Kindly regards

Ewald

5

Hello Ewald,
Thank you very much for your suggestion.

Yes, I was able to shrink the NTFS partition from inside Windows, so the installer does detect the free space correctly. The issue is that during manual partitioning, Ubuntu will not allow me to select the main disk (KingFast 256 GB, MBR) as the bootloader installation target — the option stays greyed out.

Because of that, I suspect the problem may be related more to the overall disk layout (MBR, Legacy BIOS, Windows configuration, BitLocker, etc.) rather than NTFS write support, but I will definitely keep your ntfs-3g idea in mind in case it is connected.

Thank you again for taking the time to help!

Kind regards,
Jury

6

Since you created free space for Ubuntu from Windows you were able to create the Ubuntu partitions. 2 things you could try to test would be to turn off Secure Boot in the BIOS and also boot windows and go to your system Power settings and check to see if hibernation is off.

If neither option is successful, you do know that you can select to install Grub to the system partition (sda5 in your case) and chainload it from the windows bootloader. If you expect to use Windows more than Ubuntu this would likely be your best option. The simplest thing is to download and run EasyBCD software while booted into windows. You can do this manually of course, but using EasyBCD is much easier for novices. The link below gives a description of using EasyBCD and also has a link to its site for the download. Before running EasyBCD you will need to have successfully installed Ubuntu and installed its boot code (grub) to sda5.

https://superuser.com/questions/499617/how-can-i-add-linux-to-the-new-windows-8-boot-manager

EasyBCD works only of legacy installs with boot code in the MBR.

1 Like
7

Thank you very much for the detailed suggestions.

Here is what I was able to check so far:

• Secure Boot:
My ThinkPad P50 shows Secure Boot State: Unsupported, so Secure Boot cannot be enabled or disabled on this machine.

• Hibernation / Fast Startup:
I ran powercfg /a before and after disabling hibernation.
Current state shows:

  • Hibernation: Not available
  • Hybrid Sleep: Not available
  • Fast Startup: Not available
    So none of these features are active.

• GRUB to /dev/sda5 and chainloading:
Thank you for describing this option. If the normal installer path continues to fail, I am willing to try installing GRUB to sda5 (the Ubuntu root partition) and using Windows boot manager + EasyBCD to chainload Ubuntu.

Before I proceed with that, do you think the installer’s inability to select the bootloader device (grayed-out disk list and disabled “Next” button) is consistent with an MBR/legacy boot issue on this specific ThinkPad model?

Thank you again for your help.

8

I am a bit confused.
MIcrosoft has required vendors to install Windows in UEFI boot mode with only gpt partitioning since 2012. Since about 2020 vendors may call it BIOS, but it now is UEFI only.

Does Windows still boot? Did you install Windows yourself in the old BIOS/MBR boot mode? MIcrosoft has allowed that only to support pre-2012 systems where large users wanted Windows 8 on both old & newer systems.

With old BIOS boot mode and one drive, you only have one MBR for booting. Grub only boots working Windows. So if Windows updates turn on fast startup, or NTFS needs chkdsk you need to boot Windows. So you need both a Windows repair flash drive and Ubuntu live installer to make repairs.

Lets see details on your configuration. And you can use Boot-Repair to make repairs later, when needed.
Please copy & paste the pastebin link to the BootInfo summary report ( do not post report), do not run the auto fix till reviewed.
Use often updated ppa version with your USB installer or any working install over somewhat older ISO or run update in ISO to make it current.
Boot-Repair - Community Help Wiki &
https://sourceforge.net/p/boot-repair/home/Home/

1 Like
9

Thank you for the information.

I bought this Lenovo ThinkPad P50 refurbished, so I don’t know what Windows version it originally shipped with. It did not come with Windows 10 originally, so it’s possible that an earlier Windows version or a non-standard installation was used before it was refurbished.

Currently, Windows 10 does boot normally, but the disk is clearly using MBR/Legacy rather than GPT/UEFI, which I now understand is unusual for a system of this age. I did not install Windows myself — it came preinstalled in this Legacy/MBR configuration.

If needed, I can run Boot-Repair and provide the BootInfo summary link for further analysis. Please let me know if you want me to gather that information now.

10

It may have been an update from Windows 7 which was normally BIOS/MBR, but late versions could be UEFI with Secure Boot off.

I like to run the Boot-Repair report for my own documentation. I copy the report into /home, so part of my normal backup. That way I know a lot of details, just in case of something major going wrong.

Use often updated ppa version with your USB installer or any working install over somewhat older ISO or run update in ISO to make it current.
Boot-Repair - Community Help Wiki &
https://sourceforge.net/p/boot-repair/home/Home/

11

Thank you for the detailed explanation and the links.
Here is my Boot-Info Summary report generated from Boot-Repair (run from the live USB):

https://paste.ubuntu.com/p/SWFN9jjbKJ/

To clarify my system history:
I purchased this Lenovo ThinkPad P50 (Model 20EQS34100) refurbished, and I’m not sure what Windows version it originally shipped with. It may indeed have been upgraded from Windows 7 at some point. Currently it runs Windows 10 in Legacy/MBR mode, and Secure Boot is unsupported according to System Information.
If you can review the Boot-Info report and advise on the next steps to make Ubuntu installable (or whether chainloading via EasyBCD is preferable), I would greatly appreciate it.

Thank you again for your help.

12

The link to Boot-Repair report says it does not exist. Try again or correct entry. It should just be a copy & paste so correct.

Best for your own reference to copy the report into your /home for your backups to include it. Repair is normally stored in /var/logs/boot-repair. Directory may include some drive list & logs, but you want the .txt report.

1 Like
13

Hi oldfred,
Sorry for the delay — I had to reboot into a live session again and regenerate the Boot-Info files properly.
Here are the two requested text files:

Boot-Info summary (.txt):
https://paste.ubuntu.com/p/JkkBplHV3V/

Boot-Repair log (.log):
https://paste.ubuntu.com/p/PcGzyCym5K/

Please let me know if they display correctly this time and if you need anything else.
Thank you for your patience and help!

14

The boot repair log link shows but the Boot-Info summary shows ‘does not exist’.

15

Sorry — the earlier Boot-Info link was uploaded incorrectly.
Here is the correct Boot-Info summary:

https://paste.ubuntu.com/p/TzpNxnRBNv/

Thank you for your patience.

16

The link in your last post is again to the log file and not the output of the Create BootInfo Summary. The log file does show a number of messages showing an attempt to create the summary.

17

When you run the summary report, it should offer to upload to pastebin the Summary Report. You do not have to manually copy file like you are with the log file. After it copies it, it will give you a pastebin link to copy to us.

Not sure I ever have reviewed logfile. Its more for when you have issues running Boot-Repair.

18

Here is the correct Boot-Info Summary link generated by Boot-Repair (not the log file):
https://paste.ubuntu.com/p/96HykzhrbH/

19

Thank you for the explanation.
Here is the correct Boot-Info Summary link generated by Boot-Repair (not the log file):
https://paste.ubuntu.com/p/96HykzhrbH/

20

Shows an old BIOS install of Windows on MBR partitioned drive with Ubuntu in the extended partition in sda5 & swap in sda6.
Windows in BIOS mode will only install/work on MBR. Winodws in UEFI mode must have gpt partitioning. Conversion from MBR to gpt totally erases entire drive, so if you want to convert, you have to have good backups. Best to convert when getting new drive or do not have much to backup.

You booted installer/Boot-Repair in UEFI mode. You technically can have Windows in BIOS mode booting from MBR and Ubuntu on old MBR booting from an ESP. But then can only select boot from UEFI/BIOS one time boot menu.

Disadvantage of BIOS dual boot on one drive is you only have one MBR for booting. Windows in MBR will not boot Ubuntu, but grub will boot working Windows. But working means, no fast startup, no hibernation, and no chkdsk required. Windows updates often turn fast startup back on. YOu then have to boot Windows directly to make repairs in Windows, and have to temporarily restore the Windows boot loader to MBR to boot it. Then restore grub to dual boot. Or best to have flash drive for Windows repairs & flash drive for Ubuntu https://discourse.ubuntu.com/t/a-new-ubuntu-wiki-part-1-announcement/72729repairs.

Boot-Repair is offering to restore a generic boot loader to MBR. That is one that works like Windows boot loader but dual to legal issues is not the Windows boot loader. You may be able to just use Boot-Repair to switch boot loaders, but may still need a Windows repair disk to make Windows fixes.

Long term better to reinstall Ubuntu in UEFI boot mode. Consider an SSD as much faster, but I still like to backup to an HDD and multiple flash drives.