Lets say you’re downloading roblox off the website and you run the installer, and the window just closes, what you’re left with right now is just the roblox studio app in your start menu or your desktop screen.
Right click on the roblox studio application and click “Open File Location”
From there, navigate to the previous tab and search for the “Versions” folder, and select that folder instead.
Then you’ll be able select that installer on the latest version folder, run it.
EDIT: Roblox Player & Studio won't install - #19 by GoreNest
I’ve explained it here because I did it in that exact moment, but I might have not explained it well enough here.