Cannot get Unity monodevelop to compile. Error: {E097FAD1-6243-4DAD-9C02-E9B9EFC3FFC1}'

So I was trying to follow a tutorial, and there have been 2 problems. Using monodevelop gave me that error message - I tried dealing with this through the other questions, but nothing has worked so far. Then I tried Visual Studio, but when I do this:
using UnityEngine;
public class NumberWizard : MonoBehaviour
{
// Use this for initialization
void Start()
{
//Like Java, this is literally 'printing' something to the console//
print("Welcome to Number Wizard");
print("Hope you enjoy the game!");
//Creating a variable. int = integer (countable variables)//
#pragma warning disable CS0219 // Variable is assigned but its value is never used
int max = 1000;
int min = 1;
#pragma warning restore CS0219 // Variable is assigned but its value is never used
print("The highest number that you can pick is" + max);
}
// Update is called once per frame
void Update(){
}
}
There is an error as apparently 'type numberwizard is already defined' (basically..it differs when I hover on 'Update', 'Start' and 'NumberWizard'. Also, the variables made me do that #pragma; these are all errors monodevelop does not have.

Is there any way to resolve these issues?