Fix Xamarin error – Csc.exe exited with code -1073741790. (MSB6006)
Just run Xamarin Studio as an Administrator.
The error usually means that the process cannot access a certain resource. In my case that meant insufficient rights; but it could also mean that some file is already in use; in that case – Clean the solution & Rebuild and if that doesn’t work either do a manual cleanup of the solution bu deleting the “bin” and “obj” folders for every project in your solution.