I can't install Ubuntu 18.04 alongside Windows 10

Question

Screenshot: https://i.sstatic.net/SorKT.png

So I tried to install Ubuntu 18.04 alongside with my Windows 10 Installation recently, but it doesn't show the way to install alongside with Windows 10, it just not there, only erasing Windows 10 and install Ubuntu on.

My latop is fairly old by now (Core2 Duo and doesn't have UEFI), and I just want to install Ubuntu as a lighter and faster alternative to Windows, which is a bit slow recently

btw i already install ubuntu in the past, there still the options to dual boot, when i change my hard drive and install Windows 10, it's gone

Answer 1

I run both Ubuntu and Windows 10.

After installing Windows 10, ensure you have an un-allocated partition where the Ubuntu will be installed.

Once you run the Ubuntu setup, it will appear as an option.