I’m having the same issue using VS2015 after upgrading to UE 4.18, tried going back to 4.14 and now it’s doing the same thing after having no problems earlier today before I even installed 4.18. Tons of different errors across the board (such as opening multiple instances of VS and each instance colliding with the next), but this is by far the scariest. I don’t want to continue writing code for fear of the compiler not finding it somewhere down the line.