I just downloaded Godot 3.0 beta 1 mono and wanted to test some C# on the engine.
Since Visual Studio is apparently not supported yet, I opted for MonoDevelop and the site led me to download Xamarin Studio instead--I'm on Windows 10. In Godot, I changed Mono > Editor > External Editor from "None" to "MonoDevelop", but when I click on my .cs files inside the engine, it outputs
ERROR: MonoDevelopInstance::execute: Method/Function Failed.
Help would be greatly appreciated.