Ubuntu dual boot with Windows 10 on Acer Aspire GX 785 with UEFI

Setting up an Acer Aspire GX 785 desktop PC for dual-booting Microsoft Windows 10 with Ubuntu is tricky, but not impossible. If this is above your comfort-zone, just set up a VM with Ubuntu within Windows :-).

Steps roughly:

  1. Make space on hard disk for the partitions
  2. Change BIOS security settings
  3. Create a USB disk to boot Ubuntu
  4. Install Ubuntu, creating 3 new partitions on the hard disk
  5. Fix UEFI settings

Prepare empty hard disk partition

  • In Windows, open the Disk Management tool: Right-click on Start > Disk Management
  • Make room for Ubuntu:
    • Mine had 2 ca 240GB partitions on the main disk. I removed the second one (remove any data on it first, obviously :-)).
    • If there’s only one partition, resize it to make enough room for Ubuntu (anything over you system RAM¬†+ 10GB should be good). I used ca 240GB.¬†
  • Restart Windows, double-check that things still work. Breathe.

Get into BIOS


  • If you know BIOS boot keys, use them on reboot :-). On the Acer Aspire GX it’s DEL to get into BIOS, and F12 to change the boot setting.¬†


  • Use Windows 10:¬†Start > Settings > Update & Security > Recovery > Advanced startup > Restart now > Troubleshoot > Advanced options > UEFI Firmware Settings > Restart¬†

When booting, briefly before the Windows spinner comes, you should see a line on the bottom of the screen giving you a few seconds to hit the Boot or BIOS key.

More information. Other computers may have other boot or BIOS keys to hit.

Change BIOS security / boot settings

  • Enter the BIOS on rebooting.
  • Add a supervisor password: Security > Security Option > Setup // Security > Change Supervisor Password (you need to do this to disable Secure Boot)
  • Disable secure boot: Authentication > Secure Boot > Disabled
  • Save & restart (F10)

Make a Ubuntu Live USB key

  • Follow the official Ubuntu Live-USB instructions¬†& try it out:
  • Reboot
  • Select Boot menu (F12), Enter password
  • Select USB stick (eg “UEFI: Sony Storage Media PMAP, Partition 1”)
  • You should now see a menu with “Try out …” and “Install …”

Install Ubuntu from USB

  • Select “Install …” from the USB stick.
  • Select language, connect to your wifi or network.
  • Optional: select checkboxes for “Download updates” & “Install 3rd party software”. (these take a little bit longer, so if you’re trying several times, skip them.)
  • Installation type: Something else.

You’ll now need to create the partitions. You need: 1x boot (ca 200MB), 1x primary, 1x swap (RAM sized). You should see the block you freed up under Windows as “Free space”. This is where all of these go.

  • New boot: Select “free space”. Click “+” below. Enter size: 200MB / Type: Primary / Location: Beginning / Use as: EFI System Partition / OK (This is where your Ubuntu boot / Grub will end up.)
  • New swap: Click “+”. Enter: Size: 32000MB (matching 32GB RAM, if you have it) / Type: Primary / Location: beginning / Use as: swap area / OK
  • New primary: Click “+”. Enter: size (it’ll show the full size, keep it) / Type: Primary / Location: Beginning / Use as: Ext4 journaling file system / Mount point: “/” (without quotes) / OK

You should now see ca (FYI naming: /dev/sda1 -> “sd” = disk, “a” = first disk, “1” = first partition)

previously existing:

  • (free space)
  • /dev/sda1 efi 104MB (this is your Windows boot area)
  • /dev/sda2 16MB unknown (no idea)
  • /dev/sda3 ntfs 255455MB (Windows; size can vary)
  • /dev/sda4 ntfs 1073MB (this is the recovery area)¬†


  • /dev/sda5 efi 200MB (your Ubuntu boot area)
  • /dev/sda6 swap 32000MB (your swap)
  • /dev/sda7 ext4 / 233257MB (Ubuntu, size can vary)


  • Select your new Ubuntu boot area as “Device for boot loader installation”: /dev/sda5
  • Double-check settings :-)
  • Click: Install now
  • Select time zone, keyboard layout (can be changed later).
  • Enter your name, pick a computer name, select a username, enter a password.¬†
  • Wait for installation to complete.
  • Reboot, but wait, there’s more!

Jiggle the options

  • Hit F12 to select boot menu, enter your password. You will likely still just have Windows & your USB stick.¬†
  • Boot to the USB stick.
  • Select: Try Ubuntu without installing
  • Ubuntu will come up. Connect to the network or wifi (top right).
  • Open a terminal window: Ctrl-Alt-T
  • Run these commands:
sudo add-apt-repository ppa:yannubuntu/boot-repair  
sudo apt-get update  
sudo apt-get install boot-repair  
  • In boot-repair, choose “Advanced options” and double-check:
    Main options: [x] Reinstall GRUB, [x] Use standard EFI file
    GRUB location: OS to boot: sda7 (Ubuntu). [x] Separate boot/efi partition: sda5 (match these as appropriate)

  • Click Apply

  • Double-check boot settings with this command line:

    efibootmgr -v

  • You should see 3 entries:

Boot0000\*: Windows (...)  
Boot0001\*: ubuntu (...)  
Boot0002\*: UEFI (...your USB stick...)

All 3 should have an asterix ("*") next to the number. This means they’re active entries. If you check before boot-repair, you’ll have all 3 entries, but only Windows & your USB stick will have the asterix.

Pray & reboot

  • Reboot, select Boot menu (F12), enter password.
  • You should now see 3 entries: ubuntu, Windows Boot Manager, UEFI: (…your USB stick…)
  • Rejoice, but verify.
  • Select “ubuntu”.¬†
  • The GRUB ubuntu menu will show up. Select “ubuntu”. You should now have Ubuntu open.¬†
  • Log in with the username / password you defined.
  • Reboot, select Boot menu (F12), enter password, select Windows.
  • Windows should start up.
  • Get yourself another drink & mess with your operating systems.

Life is good.

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