Manjaro installation: Cannot establish Dual boot system

[jolexin]

In 2021 I bought a PC Acer Aspire xxx. As usual, Windows was pre-installed there. First I reduced the Windows partition as much as possible and created more partitions, including a 30 G partition for Ubuntu Linux. I installed Ubuntu i.e.

• first created a bootable USB stick,
• then booted Ubuntu from this stick
• invoked the (GUI) installer in Ubuntu. The result was a dual-boot PC. After switch-on, I could choose between Windows and Ubuntu Linux.

Recently I decided to change to Manjaro Linux. I repeated the above process, i.e.

• first created a bootable USB stick,
• booted Manjaro from this stick
• invoked the (GUI) installer in Manjaro. In the installion process I determined that Manjaro should be installed on the partition where Ubuntu was before. I noticed that during the process the OS Prober did not recognize Windows.

The result of the process was undesireable. When I switch on my PC, the GRUB menu appears, but I can only “choose” Manjaro, Windows is not offered. That surprises me, because I did the same as in 2021. Note that I am familiar with that installation process; I have done it many times.

I played with the Options of the Acer PC Start Menu. I noticed that it has got a boot mode called UEFI, which is coupled with “secure boot”. With these parameters it is impossible to boot Manjaro from the stick. The only possibility to boot Manjaro from the stick is to choose boot mode “legacy”; then “secure boot” vanishes. I cannot choose boot mode UEFI without secure boot That is presumably why the installed Manjaro also boots in “legacy” mode.

To boot Windows, I must go into the Acer PC Start Menu, switch to boot mode to UEFI (coupled with secure boot). Then Windows boots, the GRUB menu does not appear, there is no choice of Manjaro.

Why is did the recent Manjaro installation process yield a different result? Can anyone explain that?

Additional remark: When I boot Manjaro, I can look into the partitions. In the Manjaro partition I can see a directory /boot/grub with a grub.cfg file. In the EFI partition there is only Windows stuff, no hint of Manjaro or GRUB.

[cscs]

You cannot mix Traditional-BIOS and UEFI installations.

Well, you can have them both at the same time, but they wont be able to both be managed by a bootloader such as grub. IE - with this setup it will be impossible to show both windoze and linux from the grub boot menu.

It seems that you report it appears impossible to disable Secure Boot while using EFI mode. This behavior should be adjustable in some fashion. Maybe consult your manufacturers documentation.

( I recall odd examples from various models including an admin password needing to be set before secure boot could be disabled )

You want them both to be on the same mode if you want them manageable by the same bootloader.

This discrepancy was observed because Ubuntu supports Secure Boot out of the box.

Arch/Manjaro can support it … but you must use self-signed keys, etc.

I suggest you investigate ways to disable secure boot, and if/when successful then reinstall manjaro under UEFI mode (boot the Live-USB in EFI mode).

[Aragorn]

You have installed Windows in UEFI mode, with Secure Boot enabled, and you have installed Manjaro in legacy BIOS emulation mode. These two boot modes are mutually incompatible.

Even though Manjaro works well in legacy mode, it actually prefers UEFI boot, and given that you have installed Windows in UEFI mode already, UEFI boot is the way to go. But you must disable Secure Boot and then reinstall Manjaro in UEFI mode.

You will probably have to disable legacy BIOS emulation in the firmware first, and then delete the Windows Secure Boot keys in the CMOS memory before you can switch off Secure Boot. Consult the manual of your motherboard on how to do this.

Alternatively, you can set up Manjaro to work with Secure Boot, but you will have to do this yourself, because we offer no support for that. Information on how to enable Secure Boot support can be found in the Arch Wiki.

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P.S.: Boot issues have nothing to do with Xfce, which is a desktop environment. I have moved your thread, but for the future, please be mindful where you post your threads. The Xfce category is specifically for problems with or questions about the Xfce desktop environment.