The system always maintains the desired number of prebuilt workspaces for the active template version.

When external dependencies change (such as AMI updates, base image changes, or configuration drift) without a template version update, you can invalidate presets to force their prebuilt workspaces to be recreated.

This is useful when:

- A base VM image or container image has been updated externally

- Infrastructure configuration has drifted from the desired state

- You want to ensure prebuilt workspaces use the latest dependencies without publishing a new template version

To invalidate presets:

1. Navigate to**Templates** and select your template.

1. Go to the**Prebuilds** tab.

1. Click**Invalidate Prebuilds**.

1. Confirm the action in the dialog.

Once presets are invalidated, the next reconciliation loop run will delete the old prebuilt workspaces and create new ones to maintain the desired instance count.

The process typically completes within a few reconciliation cycles (the interval is controlled by`CODER_WORKSPACE_PREBUILDS_RECONCILIATION_INTERVAL`, which defaults to 15 seconds).