Custom Unity Editor Issue

I have this code:

using UnityEngine;
using UnityEditor;
using System.Diagnostics;

public class UnityEditorClass {

    [MenuItem("Tools/Build Project")]
    public static void BuildGame()
    {
        //get the path
        var path = EditorUtility.SaveFolderPanel("Save Project", "C:/Projects/MyClasses/", "Test");
        //get level name
        string[] levels = { "C:/Projects/MyClasses/GSP290/MyFirstGame/Assets/Scene/MyTestScene.unity" };
        
        // Build player
        BuildPipeline.BuildPlayer(levels, path + "/Test.exe", BuildTarget.StandaloneWindows, BuildOptions.None);
        
        // Copy a file from the project folder to the build folder, alongside the built game.
        FileUtil.ReplaceFile("C:/Projects/MyClasses/GSP290/MyFirstGame/Assets/vector2.dll", path + "/" + "vector2.dll");
        FileUtil.ReplaceFile("C:/Projects/MyClasses/GSP290/MyFirstGame/Assets/matrixHelper.dll", path + "/" + "matrixHelper.dll");

        // Run the game (Process class from System.Diagnostics).
        Process proc = new Process();
        proc.StartInfo.FileName = path + "Test.exe";
        proc.Start();
    }
}

It works fine except, that it doesn’t recognize the file specified when it auto-runs. It gives me this error:

Win32Exception: The system cannot find the file specified.

If anyone has come across this problem and knows how to fix it please share and thanks in advance!

This exception corresponds to your usage of Process rather then the Unity editor API. You may find the following Q&A from StackOverflow helpful: