# Deregistering an Amazon ECS task definition revision using the console
<a name="deregister-task-definition-v2"></a>

You can deregister the task definition revision so that it no longer displays in your `ListTaskDefinition` API calls or in the console when you want to run a task or update a service.

When you deregister a task definition revision, it is immediately marked as `INACTIVE`. Existing tasks and services that reference an `INACTIVE` task definition revision continue to run without disruption. Existing services that reference an `INACTIVE` task definition revision can still scale up or down by modifying the service's desired count.

You can't use an `INACTIVE` task definition revision to run new tasks or create new services. You also can't update an existing service to reference an `INACTIVE` task definition revision (even though there may be up to a 10-minute window following deregistration where these restrictions have not yet taken effect).

**Note**  
When you deregister all revisions in a task family, the task definition family is moved to the `INACTIVE` list. Adding a new revision of an `INACTIVE` task definition moves the task definition family back to the `ACTIVE` list.  
At this time, `INACTIVE` task definition revisions remain discoverable in your account indefinitely. However, this behavior is subject to change in the future. Therefore, you should not rely on `INACTIVE` task definition revisions persisting beyond the lifecycle of any associated tasks and services.

## Amazon CloudFormation stacks
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The following behavior applies to task definitions that were created in the new Amazon ECS console before January 12, 2023.

When you create a task definition, the Amazon ECS console automatically creates a CloudFormation stack that has a name that begins with `ECS-Console-V2-TaskDefinition-`. If you used the Amazon CLI or an Amazon SDK to deregister the task definition, then you must manually delete the task definition stack. For more information, see [Deleting a stack](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/cfn-console-delete-stack.html) in the *Amazon CloudFormation User Guide*.

Task definitions created after January 12, 2023, do not have a CloudFormation stack automatically created for them.

## Procedure
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**To deregister a new task definition (Amazon ECS console)**

1. Open the console at [https://console.amazonaws.cn/ecs/v2](https://console.amazonaws.cn/ecs/v2).

1. From the navigation bar, choose the region that contains your task definition.

1. In the navigation pane, choose **Task definitions**.

1. On the **Task definitions** page, choose the task definition family that contains one or more revisions that you want to deregister.

1. On the **task definition Name** page, select the revisions to delete, and then choose **Actions**, **Deregister**.

1. Verify the information in the **Deregister** window, and then choose **Deregister** to finish.