Only choose build 10586 if you absolutely need that specific environment.
If you are downloading this ISO to install on a modern PC (Intel 12th gen, AMD Ryzen 5000/7000, etc.), you will face significant hurdles: windows 10 version 1511 build 10586 iso
: Included performance improvements to help tasks run faster than on Windows 7 and added the option to install apps on different drives . Only choose build 10586 if you absolutely need