In case of any OS installation, you need to make a backup beforehand anyway. So just backup everything you need to a different hard drive, that won’t be present during installation. Then install Windows. Override the Windows Bootloader with GRUB2. If you have 2 hard drives within your computer, it is even easier. Install Linux to the first one, Windows to the second one and all you have to do after all is to change the boot order within your UEFI for the Linux HDD to be first in the chain.
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Q1: How do I install Ubuntu, Kubuntu, Xubuntu, Ubuntu MATE, Linux Mint, Peppermint OS, LXLE or any…
You can follow any instructions on setting up dual boot. The only difference is, that you have to use one drive for one OS and the other one, for the other OS. This is much easier. So just do it.