### Author:  [@Wobbers](https://discussions.unity.com/u/Wobbers)
#### Post date: [January 20, 2020, 10:08pm UTC](https://discussions.unity.com/t/entitymanager-exists-returns-true-after-entity-was-destroyed/773225/1 "2020-01-20T22:08:25Z")
So I have a ComponentSystem that destroys Entities and one that checks components on Entities. The destroy-System runs shortly before the check-System (but both are ComponentSystems, so both on the Main Thread, right?)
Now when I am checking the Components of an Entity that was destroyed the same frame, EntityManager.Exists returns true, but the Component of the Entity I am trying to access already got removed, so I get an `ArgumentException: A component with type:Translation has not been added to the entity.`
Is this a bug or are there some multithreaded/other things going on that have to be kept in mind when using EntityManager.Exists?
(Using Entities 0.5.0)
Code:
```csharp
// Runs first
public class DeathSystem : ComponentSystem
{
protected override void OnUpdate()
{
Entities.ForEach((Entity e, ref Health health) =>
{
if (health.Value <= 0)
{
Debug.Log("Entity Died: " + e);
EntityManager.DestroyEntity(e);
// Same result with PostUpdateCommands.DestroyEntity(e)
}
});
}
}
```
```csharp
// Runs second
public class DummyKISystem : ComponentSystem
{
protected override void OnUpdate()
{
Entities.ForEach((ref DummyKIComponent dummy, ref Translation translation, ref Rotation rotation, ref MovementSpeed speed) =>
{
if (dummy.CurrentTarget == Entity.Null)
{
...
}
else if (!EntityManager.Exists(dummy.CurrentTarget))
dummy.CurrentTarget = Entity.Null;
else
{
if (!EntityManager.HasComponent(dummy.CurrentTarget))
Logger.Log("Blargh! " + dummy.CurrentTarget);
// ... (Access Translation Component)
}
});
}
}
```
Result:
---
### Author:  [@edalbeci](https://discussions.unity.com/u/edalbeci)
#### Post date: [January 20, 2020, 10:25pm UTC](https://discussions.unity.com/t/entitymanager-exists-returns-true-after-entity-was-destroyed/773225/2 "2020-01-20T22:25:17Z")
I unfortunately don’t have a solution, but did you omit or forget a [UpdateBefore(typeof(DeathSystem))] for DummyKISystem? I don’t know about ForEach but PostUpdateCommands is definitely run on the main thread, sequentially, per [the official Command Buffer docs](https://docs.unity3d.com/Packages/com.unity.entities@0.1/manual/entity_command_buffer.html).
To remove the possibility of a race condition, I made just one system:
```csharp
public class TestComponentSystem : ComponentSystem {
protected override void OnUpdate()
{
int n = 0;
Entities.ForEach((Entity e) =>
{
UnityEngine.Debug.Log(EntityManager.Exists(e));
PostUpdateCommands.DestroyEntity(e);
n++;
});
UnityEngine.Debug.Log(n);
}
}
```
The output is consistent with yours though – the entity is, oddly enough, never destroyed. (The system continues to iterate over the same entities, even after the update function completes and the next frame is run)
---
### Author:  [@schaefsky](https://discussions.unity.com/u/schaefsky)
#### Post date: [March 1, 2020, 9:04pm UTC](https://discussions.unity.com/t/entitymanager-exists-returns-true-after-entity-was-destroyed/773225/3 "2020-03-01T21:04:51Z")
> [@Wobbers](#):
>
> …
> Now when I am checking the Components of an Entity that was destroyed the same frame, EntityManager.Exists returns true, but the Component of the Entity I am trying to access already got removed, so I get an `ArgumentException: A component with type:Translation has not been added to the entity.`
I am having the same problem, did you find a solution?
---
### Author:  [@RoughSpaghetti3211](https://discussions.unity.com/u/RoughSpaghetti3211)
#### Post date: [March 1, 2020, 9:36pm UTC](https://discussions.unity.com/t/entitymanager-exists-returns-true-after-entity-was-destroyed/773225/4 "2020-03-01T21:36:00Z")
I would think that the second system would implicitly create a entity query in the lambda so that you don’t have to use the EntiyManager inside the function.
---
### Author:  [@Wobbers](https://discussions.unity.com/u/Wobbers)
#### Post date: [March 2, 2020, 3:32am UTC](https://discussions.unity.com/t/entitymanager-exists-returns-true-after-entity-was-destroyed/773225/5 "2020-03-02T03:32:44Z")
> [@schaefsky](#):
>
> I am having the same problem, did you find a solution?
Turns out there are types of Components, which can keep an Entity alive after destroying it:
[https://docs.unity3d.com/Packages/com.unity.entities@0.0/manual/system\_state\_components.html](https://docs.unity3d.com/Packages/com.unity.entities@0.0/manual/system_state_components.html)
In my case it was a GhostSystemStateComponent from the NetCode Package.
I guess in these cases we have to do a HasComponent check to be completely sure.