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

Solution 1:

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.