I really dont remember. I was just trying to make a struct out of TK’s buoyancy location and density values. The error only showed up in VS for me cause I had the wrong syntax, then fixed it, built it, Was fine and launched the project with changes no problem. So I dunno thats related to unrealbuildtool and your code. I’d guess its an in your code somewhere. Remove parts of your code peice by peice till you find the problem… thats basic debugging it sucks buts its one way to figure it out.