Ubuntu – Installation problems with GRUB, can only install by reinstalling Windows in legacy mode but need to keep in UEFI mode


I've been trying to install Kubuntu 18.04 and I keep running into the same problem of the installer getting to the point where it needs to install grub and fails with the message:

Can't install grub on sda

After many hours of troubleshooting, I realized that I can get it to install if I reinstall Windows in non-EFI mode, however, this was causing some weird problems with my motherboard so it's no longer an option. I came to this conclusion via checking Disk Management on Windows. As seen in this image…

Disk Management

there is an efi partition. Whenever Kubuntu would install, there wouldn't be an efi partition. So I'm assuming my current Windows install is an UEFI based one. Also, when Windows is installed in UEFI mode, Disk Management initializes the other drives as GPT instead of MBR.

So my question would be what do I need to do (if it's possible) to install Kubuntu while keeping windows in UEFI mode?

Let me know if there is any more information that you need.

Best Answer

Boot Live USB in UEFI Mode

If you install Windows in UEFI mode, you will have to install Kubuntu also in UEFI mode.

You should select the boot from "UEFI something USB" or "USB something UEFI" when you boot from the Live USB to install Kubuntu.

If you boot from the LiveUSB in the UEFI mode you will see this screen:

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On the other hand if you boot from the USB in the BIOS/Legacy mode you will see:

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Immediately followed by:

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See for more details https://help.ubuntu.com/community/UEFI

Also make sure Fast Boot is disabled in Windows.

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