Why windows and Mac are missing from target platform while installing?

i have screenshot my of my windows laptop

i am not sure on what section should i be posting it so i am posting it here, i hope you guys will take a look at this. and one more thing that i didn’t get any such missing platform problem when i was installing UE4.11 or something 2 or 3 months ago.

Hi SanketVaria,

Hi VoidGoat,

Do you not see these listed when you scroll up in this window?