Access is denied. (os error 5)

There is absolutely no way I can imagine that Option is causing that error. That'd be like turning on the "Hide Taskbar" setting causing your GPU to catch fire.

My first suspect would be a virus scanner behaving badly. Failing that, perhaps the editor you're using is doing something weird (try compiling and running the code without the IDE running at all). Next would be something wrong with your Rust install (try removing and reinstalling it from scratch). Next would be very strangely configured security permissions on that folder, or one of its parents.

If it's not any of those, consider an exorcist because your machine might be haunted.