Comment by seritools

To clarify, it works in 98/Me mode because I added a fallback implementation to Rust9x for these systems, as the flag in question is not supported.

AFAICT it is supported since NT 3.1, though, and it worked fine on all NT-based systems I've tested so far, so my guess would be a ReactOS API bug.

The commit adding the 9x/Me fallback implementation:

https://github.com/rust9x/rust/commit/3a3eddb0044c6d03357a75...