"running on Windows" vs. "running under Windows" [duplicate]
Solution 1:
Neither is more natural. Both are metaphors. There are no natural English words for software.
So, which preposition one uses depends on which metaphor one is employing. If one doesn't know that, one shouldn't be writing documentation.
On Windows™ uses a two-dimensional metaphor, which is almost automatic, since a window is in fact a two-dimensional object, and refers to the monitor screen. That's very common, and requires on.
Under Windows™, on the other hand, refers to the root task of an OS, which is to define, manage, and regulate all other programs, hence invoking a social hierarchic UP/DOWN metaphor (under the old King, under the new administration, etc.), which licenses use of under.
Solution 2:
This first is more natural although I believe that the second is the more original.
Originally operating systems would be seen roughly like a set of rules, in which case you run "under" a set of rules. Nowadays an operating system is seen as a basis for building things upon, like a foundation, in which case you run "on" a foundation.
Both would be valid. I would prefer the first.