- If you have 2 hard disks you can install Windows 10 on the one, and Linux on the second and then when booting from another than the default choose the other,
- If you have one hard disk, first install Windows 10; don't use the full disk but leave enough space to install Linux later. This is dual boot and you have to choose at each boot what OS to boot into.
- Or install Linux in a virtual hard drive under Windows 10.
I want to install window 10 and Linux on my computer without losing any data.

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