Reference getting lost when building the project

When try to buid in Unity, the project loses reference in 'project_name.Editor' (in Solution, VS) and deletes all files in the folder: /Library/ScriptAssemblies (The references are related to Assembly-UnityScript). This causes almost a thousand errors and it doesn't build the project. If i click Play game in the Editor, it works fine, the problem only happens when i build it.

Firstly you can click Play game in the Editor and see that it really works. But, if you go in the menu File->Build Settings->Build it will start trying to build and then it will lose references and give you lots of errors. The references are related to Assembly-UnityScript.

I work with Windos 8.1 (x64), Unity 5.6.1f1(x82), VSFU 3.1.0.0. My builds need to be on x86.