System not working

I have just copied the Rotator.cs from one of the Unity example videos, attached it to a cube but it is not working. Entity Debugger shows RotatorSystem as 'not run'. If I delete the foreach block it runs. Unity 2018.2.6f1

Code (CSharp):

1. using Unity.Entities;
2. using UnityEngine;
3.  
4. class Rotator : MonoBehaviour
5. {
6.     // The data - editable in the inspector
7.     public float Speed;
8. }
9.  
10. class RotatorSystem : ComponentSystem
11. {
12.     struct Components
13.     {
14.         // Define what components are required for this
15.         // ComponentSystem to handle them.
16.         public Transform transform;
17.         public Rotator rotator;
18.     }
19.  
20.     override protected void OnUpdate()
21.     {
22.         // We can immediately see a first optimization.
23.         // We know delta time is the same between all rotators,
24.         // so we can simply keep it in a local variable
25.         // to get better performance.
26.         float deltaTime = Time.deltaTime;
27.  
28.         // ComponentSystem.GetEntities<Group>
29.         // lets us efficiently iterate over all GameObjects
30.         // that have both a Transform & Rotator component
31.         // (as defined above in Group struct).
32.         foreach (var e in GetEntities<Components>())
33.         {
34.             e.transform.rotation *= Quaternion.AngleAxis(e.rotator.Speed * deltaTime, Vector3.up);
35.         }
36.     }
37. }

 

Have you copied bootstrap too?

 

I followed this video. I didn't do anything about bootstrapping.
https://unity3d.com/learn/tutorials/topics/scripting/introduction-ecs?playlist=17117

This same example works on my work computer.

 

I suggest check upon existing samples, if you haven't yet.

https://forum.unity.com/threads/new-samples-release-is-out-0-0-10.546722/
Specifically Two Stick example, of Classic OOP, Hybrid and Pure ECS

 

You are right, I shouldn't stay stuck with this simple example but I was just curious. Thank you.

 

It works, thanks a lot. I knew it was a 'minor' detail.

 

I also noticed if one of the components is missing on the gameobject, the entity will stop.

 

Did you solve the "not run" problem?