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Fix missing dual boot menu with Windows 10 and Debian on Acer laptops

Having multiple OSes on a single machine is convenient. It is also great to choose what OS to boot on startup.

Lately I went through the struggle of installing Debian alongside a pre-existing Windows 10 on a UEFI-powered machine (Acer Aspire E15). The Debian installation went fine, but I wasn't able to boot into Debian: no OS selection menu came up upon boot. What to do?

Step 0: make sure you are installing Debian the right way

Different tutorials on the Net suggest different routes. In general, you need to tweak two things before installing Debian: disable the fast startup on Windows 10 and disable secure boot in UEFI.

Disable fast startup on Windows 10

Fast startup is sort of partial hibernation of files and data. Unfortunately this creates a problem when you want to copy stuff from Debian to Windows. So let's disable it:

  1. open "Control Panel";
  2. select "Power Options";
  3. click "Choose what the power buttons do";
  4. click "Change settings that are currently unavailable";
  5. scroll down to "Shutdown settings" and uncheck "Turn on fast startup";
  6. click "Save changes";
  7. reboot.

Disable secure boot in UEFI

Secure boot is a way to stop malicious software to replace your boot loader. Unfortunately this makes Linux difficult (or impossible) to install. How to disable it:

  1. Reboot the system;
  2. press F2 to access the UEFI settings;
  3. navigate to "Boot" menu;
  4. disable "Secure Boot" as shown in picture 1. below;
  5. save, exit and restart.
Acer Aspire E15 UEFI secure boot
1. Acer's UEFI boot menu: where to disable the Secure Boot option.

Step 1: Select the proper UEFI file to load

Now you can install Debian as usual. Once finished, the new OS will be correctly installed but not yet accessible at startup. So head back to the UEFI settings (i.e. reboot and press F2) and in the "Security" tab select select an UEFI file as trusted for executing, as shown in picture 2. below. Here you are telling UEFI that there's another OS to take into account.

The interface will display a directory: browse it down until you find a file named BOOTx64.EFI, then select it. You will be able to choose a name too: that's what will be displayed in the boot order list later on.

The menu seen in picture 2. might be greyed out. If so, temporarily re-enable the secure boot as you did in the previous point: it should unlock the menu. Remember to disable secure boot once finished.

Save, exit and restart.

Acer Aspire E15 UEFI select .EFI file
2. Acer's UEFI security menu: select an UEFI file as trusted for executing.

Step 2: define a proper boot order

Take a look at picture 1. above: you will see how my boot order still gives priority to Windows Boot Manager (#9) over Debian (#10). Unfortunately the Windows Boot Manager is unable to see other OSes such as Debian and the like. If you leave it as it is you will boot straight into Windows 10 with no OS selection. You need to switch to grub, the smarter Linux boot loader which is able to handle a wider selection of operating systems.

To change that, enter the UEFI settings again (reboot + F2) and flip the boot order of Windows Boot Manager with EFI File Boot 0: Debian. Save and exit. This way, the next boot you will be prompted with the OS selection managed by grub.


Acer Answers - Windows 10: Enable or disable fast startup (link)
CNet - What is Windows 10's fast startup? (link)
Ask Ubuntu - Why disable Fast Boot on Windows 8 when having dual booting? (link)

Gonan on September 17, 2018 at 20:16
It helped a lot. thanks
Harold on December 27, 2018 at 06:44
I followed the instructions but I still boot into windows with UEFI. In legacy mode, I can boot straight into Kali linux 2018.
Ryan on May 04, 2019 at 13:54
Hi! This method ultimately worked for me but the trusted UEFI file needed to be debian/grubx64.efi, not boot/bootx64.efi. From what I've read elsewhere, Acer's UEFI implementation is broken and the boot/bootx64.efi file is the fallback, which will take you into Windows when Windows is installed. Also note, Debian 10 is expected to work with Secure Boot, so hopefully it will get a little easier in the future :)
Misurh on April 26, 2020 at 08:58
Man you are a truly hero, same host Acer e15 same distro windows debían
You made this soo easy for me
I hope you get rich
daniels on August 15, 2020 at 00:50
Great work! It helped a lot! Simple, short and precise. Only the important information. Thank you and best regards.
Juan Manuel Murillo Murillo on March 19, 2021 at 19:15
Muchisimas gracias por el soporte, precisamente mi laptop es una Acer Aspire E 15 E5-575-31Z0 y la ayuda fue insuperable.
David R on March 20, 2021 at 04:08
You have to put in a password on an acer spin in the security portion of acer bios,or you can't unlock uefi or safe boot.when you do then you can run a live os from usb stick or wipe out windows and install Linux.
My acer comes with a puny 69 gig emc? Drive,windows crowded it with 50 gigs of system and updates.I deleted older updates and got it down to 30 room for linux unless I wipe it and install linux.
David R
Revolted Acer User on June 16, 2021 at 03:48
Unfortunately I don´t have that option "UEFI file as trusted for executing". I installed Debian In a different SSD and it only lists the Windows that is installed in another SSD (M2). I didn´t thought Acer Aspire 5 was so picky and tricky to use with Linux systems. WOW
Rod on June 16, 2021 at 03:49
My Acer Aspire 5 don´t even allow me to choose Legacy, even after defining an administrator´s password. I am in complete shock by discovering that Acer is not Linux Friendly.